diff --git a/common/dialogs/dialog_page_settings.cpp b/common/dialogs/dialog_page_settings.cpp
index b9c02b651e..611f27d65f 100644
--- a/common/dialogs/dialog_page_settings.cpp
+++ b/common/dialogs/dialog_page_settings.cpp
@@ -43,7 +43,9 @@
 
 #ifdef EESCHEMA
 #include <general.h>
+#include <sch_edit_frame.h>
 #include <sch_screen.h>
+#include <schematic.h>
 #include <eeschema_settings.h>
 #endif
 
@@ -611,8 +613,11 @@ bool DIALOG_PAGES_SETTINGS::SavePageSettings()
 
 
 #ifdef EESCHEMA
+    wxCHECK_MSG( dynamic_cast<SCH_EDIT_FRAME*>( m_parent ), true,
+            "DIALOG_PAGES_SETTINGS::OnDateApplyClick frame is not a schematic frame!" );
+
     // Exports settings to other sheets if requested:
-    SCH_SCREENS ScreenList;
+    SCH_SCREENS ScreenList( dynamic_cast<SCH_EDIT_FRAME*>( m_parent )->Schematic().Root() );
 
     // Update page info and/or title blocks for all screens
     for( SCH_SCREEN* screen = ScreenList.GetFirst(); screen; screen = ScreenList.GetNext() )
diff --git a/eeschema/CMakeLists.txt b/eeschema/CMakeLists.txt
index 1d3c7e2150..effce305a0 100644
--- a/eeschema/CMakeLists.txt
+++ b/eeschema/CMakeLists.txt
@@ -216,6 +216,7 @@ set( EESCHEMA_SRCS
     sch_sheet_pin.cpp
     sch_text.cpp
     sch_validators.cpp
+    schematic.cpp
     schematic_undo_redo.cpp
     sch_edit_frame.cpp
     sheet.cpp
diff --git a/eeschema/annotate.cpp b/eeschema/annotate.cpp
index ba4e3e0d6f..13e032146a 100644
--- a/eeschema/annotate.cpp
+++ b/eeschema/annotate.cpp
@@ -28,17 +28,17 @@
 #include <confirm.h>
 #include <reporter.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 
 #include <sch_reference_list.h>
 #include <class_library.h>
 
 
-void mapExistingAnnotation( std::map<wxString, wxString>& aMap )
+void SCH_EDIT_FRAME::mapExistingAnnotation( std::map<wxString, wxString>& aMap )
 {
-    SCH_SHEET_LIST     sheets( g_RootSheet );
     SCH_REFERENCE_LIST references;
 
-    sheets.GetComponents( references );
+    Schematic().GetSheets().GetComponents( references );
 
     for( size_t i = 0; i < references.GetCount(); i++ )
     {
@@ -64,16 +64,16 @@ void SCH_EDIT_FRAME::DeleteAnnotation( bool aCurrentSheetOnly )
     {
         SCH_SCREEN* screen = GetScreen();
         wxCHECK_RET( screen != NULL, wxT( "Attempt to clear annotation of a NULL screen." ) );
-        screen->ClearAnnotation( g_CurrentSheet );
+        screen->ClearAnnotation( &GetCurrentSheet() );
     }
     else
     {
-        SCH_SCREENS ScreenList;
+        SCH_SCREENS ScreenList( Schematic().Root() );
         ScreenList.ClearAnnotation();
     }
 
     // Update the references for the sheet that is currently being displayed.
-    g_CurrentSheet->UpdateAllScreenReferences();
+    GetCurrentSheet().UpdateAllScreenReferences();
 
     SyncView();
     GetCanvas()->Refresh();
@@ -92,10 +92,10 @@ void SCH_EDIT_FRAME::AnnotateComponents( bool              aAnnotateSchematic,
 {
     SCH_REFERENCE_LIST references;
 
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( Schematic().Root() );
 
     // Build the sheet list.
-    SCH_SHEET_LIST sheets( g_RootSheet );
+    SCH_SHEET_LIST sheets = Schematic().GetSheets();
 
     // Map of locked components
     SCH_MULTI_UNIT_REFERENCE_MAP lockedComponents;
@@ -124,7 +124,7 @@ void SCH_EDIT_FRAME::AnnotateComponents( bool              aAnnotateSchematic,
         if( aAnnotateSchematic )
             sheets.GetMultiUnitComponents( lockedComponents );
         else
-            g_CurrentSheet->GetMultiUnitComponents( lockedComponents );
+            GetCurrentSheet().GetMultiUnitComponents( lockedComponents );
     }
 
     // Store previous annotations for building info messages
@@ -141,7 +141,7 @@ void SCH_EDIT_FRAME::AnnotateComponents( bool              aAnnotateSchematic,
     if( aAnnotateSchematic )
         sheets.GetComponents( references );
     else
-        g_CurrentSheet->GetComponents( references );
+        GetCurrentSheet().GetComponents( references );
 
     // Break full components reference in name (prefix) and number:
     // example: IC1 become IC, and 1
@@ -229,7 +229,7 @@ void SCH_EDIT_FRAME::AnnotateComponents( bool              aAnnotateSchematic,
         aReporter.ReportTail( _( "Annotation complete." ), RPT_SEVERITY_ACTION );
 
     // Update on screen references, that can be modified by previous calculations:
-    g_CurrentSheet->UpdateAllScreenReferences();
+    GetCurrentSheet().UpdateAllScreenReferences();
     SetSheetNumberAndCount();
 
     SyncView();
@@ -240,15 +240,13 @@ void SCH_EDIT_FRAME::AnnotateComponents( bool              aAnnotateSchematic,
 
 int SCH_EDIT_FRAME::CheckAnnotate( REPORTER& aReporter, bool aOneSheetOnly )
 {
-    // build the screen list
-    SCH_SHEET_LIST      sheetList( g_RootSheet );
     SCH_REFERENCE_LIST  componentsList;
 
     // Build the list of components
     if( !aOneSheetOnly )
-        sheetList.GetComponents( componentsList );
+        Schematic().GetSheets().GetComponents( componentsList );
     else
-        g_CurrentSheet->GetComponents( componentsList );
+        GetCurrentSheet().GetComponents( componentsList );
 
     // Empty schematic does not need annotation
     if( componentsList.GetCount() == 0 )
diff --git a/eeschema/connection_graph.cpp b/eeschema/connection_graph.cpp
index 96d170a3ce..d5d9db25ad 100644
--- a/eeschema/connection_graph.cpp
+++ b/eeschema/connection_graph.cpp
@@ -38,6 +38,7 @@
 #include <sch_sheet.h>
 #include <sch_sheet_path.h>
 #include <sch_text.h>
+#include <schematic.h>
 
 #include <advanced_config.h>
 #include <connection_graph.h>
@@ -297,7 +298,10 @@ void CONNECTION_SUBGRAPH::UpdateItemConnections()
         SCH_CONNECTION* item_conn = item->Connection( m_sheet );
 
         if( !item_conn )
+        {
             item_conn = item->InitializeConnection( m_sheet );
+            item_conn->SetGraph( m_graph );
+        }
 
         if( ( m_driver_connection->IsBus() && item_conn->IsNet() ) ||
             ( m_driver_connection->IsNet() && item_conn->IsBus() ) )
@@ -432,7 +436,7 @@ void CONNECTION_GRAPH::updateItemConnectivity( SCH_SHEET_PATH aSheet,
             for( SCH_SHEET_PIN* pin : static_cast<SCH_SHEET*>( item )->GetPins() )
             {
                 if( !pin->Connection( aSheet ) )
-                    pin->InitializeConnection( aSheet );
+                    pin->InitializeConnection( aSheet )->SetGraph( this );
 
                 pin->ConnectedItems( aSheet ).clear();
                 pin->Connection( aSheet )->Reset();
@@ -454,7 +458,7 @@ void CONNECTION_GRAPH::updateItemConnectivity( SCH_SHEET_PATH aSheet,
 
             for( SCH_PIN* pin : component->GetSchPins( &aSheet ) )
             {
-                pin->InitializeConnection( aSheet );
+                pin->InitializeConnection( aSheet )->SetGraph( this );
 
                 wxPoint pos = pin->GetPosition();
 
@@ -475,6 +479,7 @@ void CONNECTION_GRAPH::updateItemConnectivity( SCH_SHEET_PATH aSheet,
         {
             m_items.insert( item );
             auto conn = item->InitializeConnection( aSheet );
+            conn->SetGraph( this );
 
             // Set bus/net property here so that the propagation code uses it
             switch( item->Type() )
@@ -636,8 +641,9 @@ void CONNECTION_GRAPH::updateItemConnectivity( SCH_SHEET_PATH aSheet,
 void CONNECTION_GRAPH::buildConnectionGraph()
 {
     // Recache all bus aliases for later use
+    wxCHECK_RET( m_schematic, "Connection graph cannot be built without schematic pointer" );
 
-    SCH_SHEET_LIST all_sheets( g_RootSheet );
+    SCH_SHEET_LIST all_sheets = m_schematic->GetSheets();
 
     for( unsigned i = 0; i < all_sheets.size(); i++ )
     {
@@ -656,7 +662,7 @@ void CONNECTION_GRAPH::buildConnectionGraph()
 
             if( connection->SubgraphCode() == 0 )
             {
-                auto subgraph = new CONNECTION_SUBGRAPH( m_frame );
+                auto subgraph = new CONNECTION_SUBGRAPH( this );
 
                 subgraph->m_code = m_last_subgraph_code++;
                 subgraph->m_sheet = sheet;
@@ -667,15 +673,19 @@ void CONNECTION_GRAPH::buildConnectionGraph()
 
                 std::list<SCH_ITEM*> members;
 
-                auto get_items = [ &sheet ] ( SCH_ITEM* aItem ) -> bool
-                    {
-                      auto* conn = aItem->Connection( sheet );
+                auto get_items =
+                        [&]( SCH_ITEM* aItem ) -> bool
+                        {
+                            auto* conn = aItem->Connection( sheet );
 
-                      if( !conn )
-                          conn = aItem->InitializeConnection( sheet );
+                            if( !conn )
+                            {
+                                conn = aItem->InitializeConnection( sheet );
+                                conn->SetGraph( this );
+                            }
 
-                      return ( conn->SubgraphCode() == 0 );
-                    };
+                            return ( conn->SubgraphCode() == 0 );
+                        };
 
                 std::copy_if( item->ConnectedItems( sheet ).begin(),
                               item->ConnectedItems( sheet ).end(),
@@ -916,7 +926,10 @@ void CONNECTION_GRAPH::buildConnectionGraph()
         SCH_CONNECTION* connection = pin->Connection( sheet );
 
         if( !connection )
+        {
             connection = pin->InitializeConnection( sheet );
+            connection->SetGraph( this );
+        }
 
         // If this pin already has a subgraph, don't need to process
         if( connection->SubgraphCode() > 0 )
@@ -937,7 +950,7 @@ void CONNECTION_GRAPH::buildConnectionGraph()
         }
         else
         {
-            subgraph = new CONNECTION_SUBGRAPH( m_frame );
+            subgraph = new CONNECTION_SUBGRAPH( this );
 
             subgraph->m_code = m_last_subgraph_code++;
             subgraph->m_sheet = sheet;
@@ -1920,6 +1933,10 @@ int CONNECTION_GRAPH::RunERC()
 {
     int error_count = 0;
 
+    wxCHECK_MSG( m_schematic, true, "Null m_schematic in CONNECTION_GRAPH::ercCheckLabels" );
+
+    ERC_SETTINGS* settings = m_schematic->ErcSettings();
+
     for( auto&& subgraph : m_subgraphs )
     {
         // Graph is supposed to be up-to-date before calling RunERC()
@@ -1936,18 +1953,18 @@ int CONNECTION_GRAPH::RunERC()
          * format due to their TestDanglingEnds() implementation.
          */
 
-        if( g_ErcSettings->IsTestEnabled( ERCE_DRIVER_CONFLICT ) && !subgraph->ResolveDrivers() )
+        if( settings->IsTestEnabled( ERCE_DRIVER_CONFLICT ) && !subgraph->ResolveDrivers() )
             error_count++;
 
-        if( g_ErcSettings->IsTestEnabled( ERCE_BUS_TO_NET_CONFLICT )
+        if( settings->IsTestEnabled( ERCE_BUS_TO_NET_CONFLICT )
                 && !ercCheckBusToNetConflicts( subgraph ) )
             error_count++;
 
-        if( g_ErcSettings->IsTestEnabled( ERCE_BUS_ENTRY_CONFLICT )
+        if( settings->IsTestEnabled( ERCE_BUS_ENTRY_CONFLICT )
                 && !ercCheckBusToBusEntryConflicts( subgraph ) )
             error_count++;
 
-        if( g_ErcSettings->IsTestEnabled( ERCE_BUS_TO_BUS_CONFLICT )
+        if( settings->IsTestEnabled( ERCE_BUS_TO_BUS_CONFLICT )
                 && !ercCheckBusToBusConflicts( subgraph ) )
             error_count++;
 
@@ -1957,8 +1974,8 @@ int CONNECTION_GRAPH::RunERC()
         if( !ercCheckNoConnects( subgraph ) )
             error_count++;
 
-        if( ( g_ErcSettings->IsTestEnabled( ERCE_LABEL_NOT_CONNECTED )
-                || g_ErcSettings->IsTestEnabled( ERCE_GLOBLABEL ) ) && !ercCheckLabels( subgraph ) )
+        if( ( settings->IsTestEnabled( ERCE_LABEL_NOT_CONNECTED )
+                || settings->IsTestEnabled( ERCE_GLOBLABEL ) ) && !ercCheckLabels( subgraph ) )
             error_count++;
     }
 
@@ -2329,8 +2346,10 @@ bool CONNECTION_GRAPH::ercCheckLabels( const CONNECTION_SUBGRAPH* aSubgraph )
 
     bool is_global = text->Type() == SCH_GLOBAL_LABEL_T;
 
+    wxCHECK_MSG( m_schematic, true, "Null m_schematic in CONNECTION_GRAPH::ercCheckLabels" );
+
     // Global label check can be disabled independently
-    if( !g_ErcSettings->IsTestEnabled( ERCE_GLOBLABEL ) && is_global )
+    if( !m_schematic->ErcSettings()->IsTestEnabled( ERCE_GLOBLABEL ) && is_global )
         return true;
 
     wxString name = text->GetShownText();
diff --git a/eeschema/connection_graph.h b/eeschema/connection_graph.h
index 4b6caca657..744fbdd970 100644
--- a/eeschema/connection_graph.h
+++ b/eeschema/connection_graph.h
@@ -36,6 +36,8 @@
 #endif
 
 
+class CONNECTION_GRAPH;
+class SCHEMATIC;
 class SCH_EDIT_FRAME;
 class SCH_HIERLABEL;
 class SCH_PIN;
@@ -70,11 +72,20 @@ public:
         GLOBAL
     };
 
-    explicit CONNECTION_SUBGRAPH( SCH_EDIT_FRAME* aFrame ) :
-        m_dirty( false ), m_absorbed( false ), m_absorbed_by( nullptr ), m_code( -1 ),
-        m_multiple_drivers( false ), m_strong_driver( false ), m_local_driver( false ),
-        m_no_connect( nullptr ), m_bus_entry( nullptr ), m_driver( nullptr ), m_frame( aFrame ),
-        m_driver_connection( nullptr ), m_hier_parent( nullptr )
+    explicit CONNECTION_SUBGRAPH( CONNECTION_GRAPH* aGraph ) :
+              m_graph( aGraph ),
+              m_dirty( false ),
+              m_absorbed( false ),
+              m_absorbed_by( nullptr ),
+              m_code( -1 ),
+              m_multiple_drivers( false ),
+              m_strong_driver( false ),
+              m_local_driver( false ),
+              m_no_connect( nullptr ),
+              m_bus_entry( nullptr ),
+              m_driver( nullptr ),
+              m_driver_connection( nullptr ),
+              m_hier_parent( nullptr )
     {}
 
     ~CONNECTION_SUBGRAPH() = default;
@@ -126,6 +137,8 @@ public:
      */
     static PRIORITY GetDriverPriority( SCH_ITEM* aDriver );
 
+    CONNECTION_GRAPH* m_graph;
+
     bool m_dirty;
 
     /// True if this subgraph has been absorbed into another.  No pointers here are safe if so!
@@ -163,9 +176,6 @@ public:
 
     SCH_SHEET_PATH m_sheet;
 
-    // Needed for m_userUnits for now; maybe refactor later
-    SCH_EDIT_FRAME* m_frame;
-
     /// Cache for driver connection
     SCH_CONNECTION* m_driver_connection;
 
@@ -210,11 +220,11 @@ typedef std::map<NET_NAME_CODE, std::vector<CONNECTION_SUBGRAPH*>> NET_MAP;
 class CONNECTION_GRAPH
 {
 public:
-    CONNECTION_GRAPH( SCH_EDIT_FRAME* aFrame )
-            : m_last_net_code( 1 ),
+    CONNECTION_GRAPH( SCHEMATIC* aSchematic = nullptr ) :
+              m_last_net_code( 1 ),
               m_last_bus_code( 1 ),
               m_last_subgraph_code( 1 ),
-              m_frame( aFrame )
+              m_schematic( aSchematic )
     {}
 
     ~CONNECTION_GRAPH()
@@ -224,6 +234,11 @@ public:
 
     void Reset();
 
+    void SetSchematic( SCHEMATIC* aSchematic )
+    {
+        m_schematic = aSchematic;
+    }
+
     /**
      * Updates the connection graph for the given list of sheets.
      *
@@ -301,10 +316,7 @@ private:
 
     int m_last_subgraph_code;
 
-    std::mutex m_item_mutex;
-
-    // Needed for m_userUnits for now; maybe refactor later
-    SCH_EDIT_FRAME* m_frame;
+    SCHEMATIC* m_schematic;     ///< The schematic this graph represents
 
     /**
      * Updates the graphical connectivity between items (i.e. where they touch)
diff --git a/eeschema/cross-probing.cpp b/eeschema/cross-probing.cpp
index b11be51d97..0850af4876 100644
--- a/eeschema/cross-probing.cpp
+++ b/eeschema/cross-probing.cpp
@@ -36,6 +36,7 @@
 #include <sch_component.h>
 #include <sch_sheet.h>
 #include <sch_view.h>
+#include <schematic.h>
 #include <reporter.h>
 #include <netlist_exporters/netlist_exporter_kicad.h>
 #include <tools/ee_actions.h>
@@ -48,18 +49,18 @@ SCH_ITEM* SCH_EDITOR_CONTROL::FindComponentAndItem( const wxString& aReference,
                                                     const wxString& aSearchText )
 {
     SCH_SHEET_PATH* sheetWithComponentFound = NULL;
-    SCH_COMPONENT*  Component = NULL;
+    SCH_COMPONENT*  component               = NULL;
     wxPoint         pos;
     LIB_PIN*        pin = nullptr;
-    SCH_SHEET_LIST  sheetList( g_RootSheet );
+    SCH_SHEET_LIST  sheetList;
     SCH_ITEM*       foundItem = nullptr;
 
     if( !aSearchHierarchy )
-        sheetList.push_back( *g_CurrentSheet );
+        sheetList.push_back( m_frame->GetCurrentSheet() );
     else
-        sheetList.BuildSheetList( g_RootSheet );
+        sheetList.BuildSheetList( &m_frame->Schematic().Root() );
 
-    for( SCH_SHEET_PATH& sheet : sheetList)
+    for( SCH_SHEET_PATH& sheet : sheetList )
     {
         SCH_SCREEN* screen = sheet.LastScreen();
 
@@ -69,7 +70,7 @@ SCH_ITEM* SCH_EDITOR_CONTROL::FindComponentAndItem( const wxString& aReference,
 
             if( aReference.CmpNoCase( pSch->GetRef( &sheet ) ) == 0 )
             {
-                Component = pSch;
+                component               = pSch;
                 sheetWithComponentFound = &sheet;
 
                 if( aSearchType == HIGHLIGHT_PIN )
@@ -80,14 +81,14 @@ SCH_ITEM* SCH_EDITOR_CONTROL::FindComponentAndItem( const wxString& aReference,
                     if( pin )
                     {
                         pos += pin->GetPosition();
-                        foundItem = Component;
+                        foundItem = component;
                         break;
                     }
                 }
                 else
                 {
                     pos = pSch->GetPosition();
-                    foundItem = Component;
+                    foundItem = component;
                     break;
                 }
             }
@@ -97,19 +98,19 @@ SCH_ITEM* SCH_EDITOR_CONTROL::FindComponentAndItem( const wxString& aReference,
             break;
     }
 
-    if( Component )
+    if( component )
     {
-        if( *sheetWithComponentFound != *g_CurrentSheet )
+        if( *sheetWithComponentFound != m_frame->GetCurrentSheet() )
         {
             sheetWithComponentFound->LastScreen()->SetZoom( m_frame->GetScreen()->GetZoom() );
-            *g_CurrentSheet = *sheetWithComponentFound;
+            m_frame->Schematic().SetCurrentSheet( *sheetWithComponentFound );
             m_frame->DisplayCurrentSheet();
         }
 
         wxPoint delta;
-        pos  -= Component->GetPosition();
-        delta = Component->GetTransform().TransformCoordinate( pos );
-        pos   = delta + Component->GetPosition();
+        pos  -= component->GetPosition();
+        delta = component->GetTransform().TransformCoordinate( pos );
+        pos   = delta + component->GetPosition();
 
         m_frame->GetCanvas()->GetViewControls()->SetCrossHairCursorPosition( pos, false );
         m_frame->CenterScreen( pos, false );
@@ -124,7 +125,7 @@ SCH_ITEM* SCH_EDITOR_CONTROL::FindComponentAndItem( const wxString& aReference,
     else
         msg_item = _( "component" );
 
-    if( Component )
+    if( component )
     {
         if( foundItem )
             msg.Printf( _( "%s %s found" ), aReference, msg_item );
@@ -390,8 +391,7 @@ void SCH_EDIT_FRAME::KiwayMailIn( KIWAY_EXPRESS& mail )
     case MAIL_SCH_GET_NETLIST:
         if( payload.find( "quiet-annotate" ) != std::string::npos )
         {
-            SCH_SHEET_LIST sheets( g_RootSheet );
-            sheets.AnnotatePowerSymbols();
+            Schematic().GetSheets().AnnotatePowerSymbols();
             AnnotateComponents( true, UNSORTED, INCREMENTAL_BY_REF, 0, false, false, true,
                                 NULL_REPORTER::GetInstance() );
         }
@@ -405,7 +405,8 @@ void SCH_EDIT_FRAME::KiwayMailIn( KIWAY_EXPRESS& mail )
 
         {
             NETLIST_OBJECT_LIST* net_atoms = BuildNetListBase();
-            NETLIST_EXPORTER_KICAD exporter( this, net_atoms, g_ConnectionGraph );
+            NETLIST_EXPORTER_KICAD exporter(
+                    this, net_atoms, &Schematic(), Schematic().ConnectionGraph() );
             STRING_FORMATTER formatter;
 
             exporter.Format( &formatter, GNL_ALL );
@@ -428,7 +429,7 @@ void SCH_EDIT_FRAME::KiwayMailIn( KIWAY_EXPRESS& mail )
 
     case MAIL_SCH_REFRESH:
     {
-        SCH_SCREENS schematic;
+        SCH_SCREENS schematic( Schematic().Root() );
         schematic.TestDanglingEnds();
 
         GetCanvas()->GetView()->UpdateAllItems( KIGFX::ALL );
diff --git a/eeschema/dialogs/dialog_bom.cpp b/eeschema/dialogs/dialog_bom.cpp
index 0db2aeac65..f4228c7702 100644
--- a/eeschema/dialogs/dialog_bom.cpp
+++ b/eeschema/dialogs/dialog_bom.cpp
@@ -44,6 +44,7 @@
 #include <pgm_base.h>
 #include <reporter.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 
 #include <dialogs/dialog_bom_cfg_lexer.h>
 
@@ -456,7 +457,7 @@ void DIALOG_BOM::pluginInit()
 void DIALOG_BOM::OnRunGenerator( wxCommandEvent& event )
 {
     // Calculate the xml netlist filename
-    wxFileName fn = g_RootSheet->GetScreen()->GetFileName();
+    wxFileName fn = m_parent->Schematic().GetFileName();
 
     fn.SetPath( wxPathOnly( Prj().GetProjectFullName() ) );
     fn.ClearExt();
diff --git a/eeschema/dialogs/dialog_bus_manager.cpp b/eeschema/dialogs/dialog_bus_manager.cpp
index c02faf28c5..bc43639e22 100644
--- a/eeschema/dialogs/dialog_bus_manager.cpp
+++ b/eeschema/dialogs/dialog_bus_manager.cpp
@@ -22,6 +22,7 @@
 
 #include <invoke_sch_dialog.h>
 #include <sch_sheet_path.h>
+#include <schematic.h>
 
 #include "dialog_bus_manager.h"
 
@@ -192,13 +193,14 @@ bool DIALOG_BUS_MANAGER::TransferDataToWindow()
 {
     m_aliases.clear();
 
-    SCH_SHEET_LIST aSheets( g_RootSheet );
+    const SCH_SHEET_LIST& sheets = m_parent->Schematic().GetSheets();
+
     std::vector< std::shared_ptr< BUS_ALIAS > > original_aliases;
 
     // collect aliases from each open sheet
-    for( unsigned i = 0; i < aSheets.size(); i++ )
+    for( unsigned i = 0; i < sheets.size(); i++ )
     {
-        auto sheet_aliases = aSheets[i].LastScreen()->GetBusAliases();
+        auto sheet_aliases = sheets[i].LastScreen()->GetBusAliases();
         original_aliases.insert( original_aliases.end(), sheet_aliases.begin(),
                                  sheet_aliases.end() );
     }
diff --git a/eeschema/dialogs/dialog_edit_components_libid.cpp b/eeschema/dialogs/dialog_edit_components_libid.cpp
index 6f567aac68..1aa4cafa40 100644
--- a/eeschema/dialogs/dialog_edit_components_libid.cpp
+++ b/eeschema/dialogs/dialog_edit_components_libid.cpp
@@ -34,6 +34,7 @@
 #include <sch_draw_panel.h>
 #include <sch_component.h>
 #include <sch_reference_list.h>
+#include <schematic.h>
 #include <pgm_base.h>
 #include <symbol_lib_table.h>
 #include <trace_helpers.h>
@@ -423,7 +424,7 @@ void DIALOG_EDIT_COMPONENTS_LIBID::initDlg()
     // In complex hierarchies, the same component is in fact duplicated, but
     // it is listed with different references (one by sheet instance)
     // the list is larger and looks like it contains all components
-    SCH_SHEET_LIST sheets( g_RootSheet );
+    const SCH_SHEET_LIST& sheets = GetParent()->Schematic().GetSheets();
     SCH_REFERENCE_LIST references;
     // build the full list of components including component having no symbol in loaded libs
     // (orphan components)
diff --git a/eeschema/dialogs/dialog_edit_label.cpp b/eeschema/dialogs/dialog_edit_label.cpp
index 7938a8e96b..29ad36367d 100644
--- a/eeschema/dialogs/dialog_edit_label.cpp
+++ b/eeschema/dialogs/dialog_edit_label.cpp
@@ -34,6 +34,7 @@
 #include <sch_text.h>
 #include <sch_component.h>
 #include <sch_reference_list.h>
+#include <schematic.h>
 #include <widgets/unit_binder.h>
 #include <dialog_edit_label_base.h>
 #include <kicad_string.h>
@@ -79,6 +80,10 @@ private:
     bool TransferDataToWindow() override;
     bool TransferDataFromWindow() override;
 
+    wxString convertKIIDsToReferences( const wxString& aSource ) const;
+
+    wxString convertReferencesToKIIDs( const wxString& aSource ) const;
+
     SCH_EDIT_FRAME* m_Parent;
     SCH_TEXT*       m_CurrentText;
     wxWindow*       m_activeTextCtrl;
@@ -204,7 +209,7 @@ DIALOG_LABEL_EDITOR::~DIALOG_LABEL_EDITOR()
 }
 
 
-wxString convertKIIDsToReferences( const wxString& aSource )
+wxString DIALOG_LABEL_EDITOR::convertKIIDsToReferences( const wxString& aSource ) const
 {
     wxString newbuf;
     size_t   sourceLen = aSource.length();
@@ -229,7 +234,7 @@ wxString convertKIIDsToReferences( const wxString& aSource )
 
             if( isCrossRef )
             {
-                SCH_SHEET_LIST sheetList( g_RootSheet );
+                SCH_SHEET_LIST sheetList = m_Parent->Schematic().GetSheets();
                 wxString       remainder;
                 wxString       ref = token.BeforeFirst( ':', &remainder );
 
@@ -255,7 +260,7 @@ wxString convertKIIDsToReferences( const wxString& aSource )
 }
 
 
-wxString convertReferencesToKIIDs( const wxString& aSource )
+wxString DIALOG_LABEL_EDITOR::convertReferencesToKIIDs( const wxString& aSource ) const
 {
     wxString newbuf;
     size_t   sourceLen = aSource.length();
@@ -280,7 +285,7 @@ wxString convertReferencesToKIIDs( const wxString& aSource )
 
             if( isCrossRef )
             {
-                SCH_SHEET_LIST     sheets( g_RootSheet );
+                SCH_SHEET_LIST     sheets = m_Parent->Schematic().GetSheets();
                 wxString           remainder;
                 wxString           ref = token.BeforeFirst( ':', &remainder );
                 SCH_REFERENCE_LIST references;
@@ -335,7 +340,7 @@ bool DIALOG_LABEL_EDITOR::TransferDataToWindow()
     {
         // Load the combobox with the existing labels of the same type
         std::set<wxString> existingLabels;
-        SCH_SCREENS        allScreens;
+        SCH_SCREENS        allScreens( m_Parent->Schematic().Root() );
 
         for( SCH_SCREEN* screen = allScreens.GetFirst(); screen; screen = allScreens.GetNext() )
         {
diff --git a/eeschema/dialogs/dialog_erc.cpp b/eeschema/dialogs/dialog_erc.cpp
index 821e4e844a..5dda2ef909 100644
--- a/eeschema/dialogs/dialog_erc.cpp
+++ b/eeschema/dialogs/dialog_erc.cpp
@@ -28,6 +28,7 @@
 #include <pgm_base.h>
 #include <sch_screen.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 #include <invoke_sch_dialog.h>
 #include <project.h>
 #include <kiface_i.h>
@@ -57,7 +58,7 @@ DIALOG_ERC::DIALOG_ERC( SCH_EDIT_FRAME* parent ) :
     EESCHEMA_SETTINGS* settings = dynamic_cast<EESCHEMA_SETTINGS*>( Kiface().KifaceSettings() );
     m_severities = settings->m_Appearance.erc_severities;
 
-    m_markerProvider = new SHEETLIST_ERC_ITEMS_PROVIDER();
+    m_markerProvider = new SHEETLIST_ERC_ITEMS_PROVIDER( &m_parent->Schematic() );
     m_markerTreeModel = new RC_TREE_MODEL( parent, m_markerDataView );
     m_markerDataView->AssociateModel( m_markerTreeModel );
 
@@ -180,9 +181,10 @@ void DIALOG_ERC::TestErc( REPORTER& aReporter )
 {
     wxFileName fn;
 
+    SCHEMATIC* sch = &m_parent->Schematic();
+
     // Build the whole sheet list in hierarchy (sheet, not screen)
-    SCH_SHEET_LIST sheets( g_RootSheet );
-    sheets.AnnotatePowerSymbols();
+    sch->GetSheets().AnnotatePowerSymbols();
 
     if( m_parent->CheckAnnotate( aReporter, false ) )
     {
@@ -192,31 +194,33 @@ void DIALOG_ERC::TestErc( REPORTER& aReporter )
         return;
     }
 
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( sch->Root() );
+    ERC_SETTINGS* settings = sch->ErcSettings();
 
     // Test duplicate sheet names inside a given sheet.  While one can have multiple references
     // to the same file, each must have a unique name.
-    if( g_ErcSettings->IsTestEnabled( ERCE_DUPLICATE_SHEET_NAME ) )
+    if( settings->IsTestEnabled( ERCE_DUPLICATE_SHEET_NAME ) )
     {
         aReporter.ReportTail( _( "Checking sheet names...\n" ), RPT_SEVERITY_INFO );
-        TestDuplicateSheetNames( true );
+        TestDuplicateSheetNames( sch, true );
     }
 
-    if( g_ErcSettings->IsTestEnabled( ERCE_BUS_ALIAS_CONFLICT ) )
+    if( settings->IsTestEnabled( ERCE_BUS_ALIAS_CONFLICT ) )
     {
         aReporter.ReportTail( _( "Checking bus conflicts...\n" ), RPT_SEVERITY_INFO );
-        TestConflictingBusAliases();
+        TestConflictingBusAliases( sch );
     }
 
     // The connection graph has a whole set of ERC checks it can run
     aReporter.ReportTail( _( "Checking conflicts...\n" ) );
     m_parent->RecalculateConnections( NO_CLEANUP );
-    g_ConnectionGraph->RunERC();
+    sch->ConnectionGraph()->RunERC();
 
     // Test is all units of each multiunit component have the same footprint assigned.
-    if( g_ErcSettings->IsTestEnabled( ERCE_DIFFERENT_UNIT_FP ) )
+    if( settings->IsTestEnabled( ERCE_DIFFERENT_UNIT_FP ) )
     {
         aReporter.ReportTail( _( "Checking footprints...\n" ), RPT_SEVERITY_INFO );
+        SCH_SHEET_LIST sheets = sch->GetSheets();
         TestMultiunitFootprints( sheets );
     }
 
@@ -273,7 +277,7 @@ void DIALOG_ERC::TestErc( REPORTER& aReporter )
         case NETLIST_ITEM::PIN:
         {
             // Check if this pin has appeared before on a different net
-            if( item->m_Link && g_ErcSettings->IsTestEnabled( ERCE_DIFFERENT_UNIT_NET ) )
+            if( item->m_Link && settings->IsTestEnabled( ERCE_DIFFERENT_UNIT_NET ) )
             {
                 wxString ref = item->GetComponentParent()->GetRef( &item->m_SheetPath );
                 wxString pin_name = ref + "_" + item->m_PinNum;
@@ -312,14 +316,14 @@ void DIALOG_ERC::TestErc( REPORTER& aReporter )
 
     // Test similar labels (i;e. labels which are identical when
     // using case insensitive comparisons)
-    if( g_ErcSettings->IsTestEnabled( ERCE_SIMILAR_LABELS ) )
+    if( settings->IsTestEnabled( ERCE_SIMILAR_LABELS ) )
     {
         aReporter.ReportTail( _( "Checking labels...\n" ), RPT_SEVERITY_INFO );
         objectsConnectedList->TestforSimilarLabels();
     }
 
-    if( g_ErcSettings->IsTestEnabled( ERCE_UNRESOLVED_VARIABLE ) )
-        TestTextVars();
+    if( settings->IsTestEnabled( ERCE_UNRESOLVED_VARIABLE ) )
+        TestTextVars( sch );
 
     // Display diags:
     m_markerTreeModel->SetProvider( m_markerProvider );
@@ -343,9 +347,8 @@ void DIALOG_ERC::TestErc( REPORTER& aReporter )
 void DIALOG_ERC::OnERCItemSelected( wxDataViewEvent& aEvent )
 {
     const KIID&     itemID = RC_TREE_MODEL::ToUUID( aEvent.GetItem() );
-    SCH_SHEET_LIST  sheetList( g_RootSheet );
     SCH_SHEET_PATH  sheet;
-    SCH_ITEM*       item = sheetList.GetItem( itemID, &sheet );
+    SCH_ITEM*       item = m_parent->Schematic().GetSheets().GetItem( itemID, &sheet );
 
     if( item )
     {
@@ -391,12 +394,14 @@ void DIALOG_ERC::OnERCItemRClick( wxDataViewEvent& aEvent )
     if( !node )
         return;
 
+    SCHEMATIC& sch = m_parent->Schematic();
+
     RC_ITEM*  rcItem = node->m_RcItem;
     wxString  listName;
     wxMenu    menu;
     wxString  msg;
 
-    switch( GetSeverity( rcItem->GetErrorCode() ) )
+    switch( sch.GetErcSeverity( rcItem->GetErrorCode() ) )
     {
     case RPT_SEVERITY_ERROR:   listName = _( "errors" );      break;
     case RPT_SEVERITY_WARNING: listName = _( "warnings" );    break;
@@ -421,7 +426,7 @@ void DIALOG_ERC::OnERCItemRClick( wxDataViewEvent& aEvent )
     {
         // Pin to pin severities edited through pin conflict map
     }
-    else if( GetSeverity( rcItem->GetErrorCode() ) == RPT_SEVERITY_WARNING )
+    else if( sch.GetErcSeverity( rcItem->GetErrorCode() ) == RPT_SEVERITY_WARNING )
     {
         menu.Append( 4, wxString::Format( _( "Change severity to Error for all '%s' violations" ),
                                           rcItem->GetErrorText( rcItem->GetErrorCode() ) ),
@@ -474,7 +479,7 @@ void DIALOG_ERC::OnERCItemRClick( wxDataViewEvent& aEvent )
         break;
 
     case 4:
-        SetSeverity( rcItem->GetErrorCode(), RPT_SEVERITY_ERROR );
+        sch.SetErcSeverity( rcItem->GetErrorCode(), RPT_SEVERITY_ERROR );
 
         // Rebuild model and view
         static_cast<RC_TREE_MODEL*>( aEvent.GetModel() )->SetProvider( m_markerProvider );
@@ -482,7 +487,7 @@ void DIALOG_ERC::OnERCItemRClick( wxDataViewEvent& aEvent )
         break;
 
     case 5:
-        SetSeverity( rcItem->GetErrorCode(), RPT_SEVERITY_WARNING );
+        sch.SetErcSeverity( rcItem->GetErrorCode(), RPT_SEVERITY_WARNING );
 
         // Rebuild model and view
         static_cast<RC_TREE_MODEL*>( aEvent.GetModel() )->SetProvider( m_markerProvider );
@@ -491,12 +496,12 @@ void DIALOG_ERC::OnERCItemRClick( wxDataViewEvent& aEvent )
 
     case 6:
     {
-        SetSeverity( rcItem->GetErrorCode(), RPT_SEVERITY_IGNORE );
+        sch.SetErcSeverity( rcItem->GetErrorCode(), RPT_SEVERITY_IGNORE );
 
         if( rcItem->GetErrorCode() == ERCE_PIN_TO_PIN_ERROR )
-            SetSeverity( ERCE_PIN_TO_PIN_WARNING, RPT_SEVERITY_IGNORE );
+            sch.SetErcSeverity( ERCE_PIN_TO_PIN_WARNING, RPT_SEVERITY_IGNORE );
 
-        SCH_SCREENS ScreenList;
+        SCH_SCREENS ScreenList( sch.Root() );
         ScreenList.DeleteMarkers( MARKER_BASE::MARKER_ERC, rcItem->GetErrorCode() );
 
         // Rebuild model and view
@@ -607,7 +612,7 @@ bool DIALOG_ERC::writeReport( const wxString& aFullFileName )
     int            err_count = 0;
     int            warn_count = 0;
     int            total_count = 0;
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = m_parent->Schematic().GetSheets();
 
     sheetList.FillItemMap( itemMap );
 
@@ -624,7 +629,7 @@ bool DIALOG_ERC::writeReport( const wxString& aFullFileName )
 
             total_count++;
 
-            switch( GetSeverity( marker->GetRCItem()->GetErrorCode() ) )
+            switch( m_parent->Schematic().GetErcSeverity( marker->GetRCItem()->GetErrorCode() ) )
             {
             case RPT_SEVERITY_ERROR:   err_count++;  break;
             case RPT_SEVERITY_WARNING: warn_count++; break;
diff --git a/eeschema/dialogs/dialog_fields_editor_global.cpp b/eeschema/dialogs/dialog_fields_editor_global.cpp
index 7f934f56d3..7dff64a1bf 100644
--- a/eeschema/dialogs/dialog_fields_editor_global.cpp
+++ b/eeschema/dialogs/dialog_fields_editor_global.cpp
@@ -36,6 +36,7 @@
 #include <refdes_utils.h>
 #include <sch_edit_frame.h>
 #include <sch_reference_list.h>
+#include <schematic.h>
 #include <tools/sch_editor_control.h>
 #include <widgets/grid_text_button_helpers.h>
 #include <widgets/wx_grid.h>
@@ -678,8 +679,7 @@ DIALOG_FIELDS_EDITOR_GLOBAL::DIALOG_FIELDS_EDITOR_GLOBAL( SCH_EDIT_FRAME* parent
     wxSize defaultDlgSize = ConvertDialogToPixels( wxSize( 600, 300 ) );
 
     // Get all components from the list of schematic sheets
-    SCH_SHEET_LIST sheets( g_RootSheet );
-    sheets.GetComponents( m_componentRefs, false );
+    m_parent->Schematic().GetSheets().GetComponents( m_componentRefs, false );
 
     m_bRefresh->SetBitmap( KiBitmap( refresh_xpm ) );
 
diff --git a/eeschema/dialogs/dialog_global_edit_text_and_graphics.cpp b/eeschema/dialogs/dialog_global_edit_text_and_graphics.cpp
index 1ef1b45a23..1ca90ac4fc 100644
--- a/eeschema/dialogs/dialog_global_edit_text_and_graphics.cpp
+++ b/eeschema/dialogs/dialog_global_edit_text_and_graphics.cpp
@@ -30,6 +30,7 @@
 #include <sch_edit_frame.h>
 #include <sch_line.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 #include <advanced_config.h>
 #include <tool/tool_manager.h>
 #include <tools/ee_selection_tool.h>
@@ -179,7 +180,7 @@ bool DIALOG_GLOBAL_EDIT_TEXT_AND_GRAPHICS::TransferDataToWindow()
     else if( selection.GetSize() )
     {
         SCH_ITEM* sch_item = (SCH_ITEM*) selection.Front();
-        SCH_CONNECTION* connection = sch_item->Connection( *g_CurrentSheet );
+        SCH_CONNECTION* connection = sch_item->Connection( m_parent->GetCurrentSheet() );
 
         if( connection )
             m_netFilter->SetValue( connection->Name() );
@@ -430,10 +431,8 @@ bool DIALOG_GLOBAL_EDIT_TEXT_AND_GRAPHICS::TransferDataFromWindow()
     if( !m_textSize.Validate( Mils2iu( 1 ), Mils2iu( 10000 ) ) )  // 1 mil .. 10 inches
         return false;
 
-    SCH_SHEET_LIST aSheets( g_RootSheet );
-
     // Go through sheets
-    for( const SCH_SHEET_PATH& sheetPath : aSheets )
+    for( const SCH_SHEET_PATH& sheetPath : m_parent->Schematic().GetSheets() )
     {
         SCH_SCREEN* screen = sheetPath.LastScreen();
 
diff --git a/eeschema/dialogs/dialog_migrate_buses.cpp b/eeschema/dialogs/dialog_migrate_buses.cpp
index 7df2c0bf96..a8974fbbbd 100644
--- a/eeschema/dialogs/dialog_migrate_buses.cpp
+++ b/eeschema/dialogs/dialog_migrate_buses.cpp
@@ -19,6 +19,7 @@
  */
 
 #include <sch_connection.h>
+#include <schematic.h>
 #include <connection_graph.h>
 #include <tool/tool_manager.h>
 #include <tool/actions.h>
@@ -72,7 +73,7 @@ DIALOG_MIGRATE_BUSES::DIALOG_MIGRATE_BUSES( SCH_EDIT_FRAME* aParent )
 void DIALOG_MIGRATE_BUSES::loadGraphData()
 {
     m_items.clear();
-    auto subgraphs = g_ConnectionGraph->GetBusesNeedingMigration();
+    auto subgraphs = m_frame->Schematic().ConnectionGraph()->GetBusesNeedingMigration();
 
     for( auto subgraph : subgraphs )
     {
@@ -172,11 +173,13 @@ void DIALOG_MIGRATE_BUSES::onItemSelected( wxListEvent& aEvent )
     auto sheet = subgraph->m_sheet;
     auto driver = subgraph->m_driver;
 
-    if( sheet != *g_CurrentSheet )
+    const SCH_SHEET_PATH& current = m_frame->GetCurrentSheet();
+
+    if( sheet != current )
     {
         sheet.LastScreen()->SetZoom( m_frame->GetScreen()->GetZoom() );
-        *g_CurrentSheet = sheet;
-        g_CurrentSheet->UpdateAllScreenReferences();
+        sheet.UpdateAllScreenReferences();
+        m_frame->Schematic().SetCurrentSheet( sheet );
         sheet.LastScreen()->TestDanglingEnds();
     }
 
diff --git a/eeschema/dialogs/dialog_netlist.cpp b/eeschema/dialogs/dialog_netlist.cpp
index 3a45c01ff4..2f87e41b2c 100644
--- a/eeschema/dialogs/dialog_netlist.cpp
+++ b/eeschema/dialogs/dialog_netlist.cpp
@@ -45,6 +45,7 @@
 #include <invoke_sch_dialog.h>
 #include <netlist_exporters/netlist_exporter_pspice.h>
 #include <eeschema_settings.h>
+#include <schematic.h>
 
 #include <eeschema_id.h>
 #include <wx/regex.h>
@@ -439,7 +440,7 @@ bool NETLIST_DIALOG::TransferDataFromWindow()
     unsigned netlist_opt = 0;
 
     // Calculate the netlist filename
-    fn = g_RootSheet->GetScreen()->GetFileName();
+    fn = m_Parent->Schematic().GetFileName();
     FilenamePrms( currPage->m_IdNetType, &fileExt, &fileWildcard );
 
     // Set some parameters
diff --git a/eeschema/dialogs/dialog_plot_schematic.cpp b/eeschema/dialogs/dialog_plot_schematic.cpp
index 55229c26d1..f98bde6d91 100644
--- a/eeschema/dialogs/dialog_plot_schematic.cpp
+++ b/eeschema/dialogs/dialog_plot_schematic.cpp
@@ -29,10 +29,10 @@
 #include <eeschema_settings.h>
 #include <kiface_i.h>
 #include <pgm_base.h>
-#include <sch_sheet.h>
 #include <settings/settings_manager.h>
 #include <ws_painter.h>
 #include <sch_painter.h>
+#include <schematic.h>
 
 // static members (static to remember last state):
 int DIALOG_PLOT_SCHEMATIC::m_pageSizeSelect = PAGE_SIZE_AUTO;
@@ -151,7 +151,7 @@ void DIALOG_PLOT_SCHEMATIC::OnOutputDirectoryBrowseClicked( wxCommandEvent& even
 
     wxFileName      dirName = wxFileName::DirName( dirDialog.GetPath() );
 
-    wxFileName fn( Prj().AbsolutePath( g_RootSheet->GetFileName() ) );
+    wxFileName fn( Prj().AbsolutePath( m_parent->Schematic().Root().GetFileName() ) );
     wxString defaultPath = fn.GetPathWithSep();
     wxString msg;
     msg.Printf( _( "Do you want to use a path relative to\n\"%s\"" ), GetChars( defaultPath ) );
diff --git a/eeschema/dialogs/dialog_print_using_printer.cpp b/eeschema/dialogs/dialog_print_using_printer.cpp
index de5389c72b..23c2f6d92e 100644
--- a/eeschema/dialogs/dialog_print_using_printer.cpp
+++ b/eeschema/dialogs/dialog_print_using_printer.cpp
@@ -33,6 +33,7 @@
 #include <settings/color_settings.h>
 #include <settings/settings_manager.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 #include <sch_sheet_path.h>
 #include <dialog_print_using_printer_base.h>
 #include <sch_painter.h>
@@ -319,10 +320,12 @@ bool DIALOG_PRINT_USING_PRINTER::TransferDataFromWindow()
 
     SavePrintOptions();
 
-    wxPrintDialogData printDialogData( m_parent->GetPageSetupData().GetPrintData() );
-    printDialogData.SetMaxPage( g_RootSheet->CountSheets() );
+    int sheet_count = m_parent->Schematic().Root().CountSheets();
 
-    if( g_RootSheet->CountSheets() > 1 )
+    wxPrintDialogData printDialogData( m_parent->GetPageSetupData().GetPrintData() );
+    printDialogData.SetMaxPage( sheet_count );
+
+    if( sheet_count > 1 )
         printDialogData.EnablePageNumbers( true );
 
     wxPrinter printer( &printDialogData );
@@ -348,7 +351,7 @@ bool DIALOG_PRINT_USING_PRINTER::TransferDataFromWindow()
 
 bool SCH_PRINTOUT::OnPrintPage( int page )
 {
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = m_parent->Schematic().GetSheets();
 
     wxCHECK_MSG( page >= 1 && page <= (int)sheetList.size(), false,
                  wxT( "Cannot print invalid page number." ) );
@@ -379,13 +382,13 @@ bool SCH_PRINTOUT::OnPrintPage( int page )
 void SCH_PRINTOUT::GetPageInfo( int* minPage, int* maxPage, int* selPageFrom, int* selPageTo )
 {
     *minPage = *selPageFrom = 1;
-    *maxPage = *selPageTo   = g_RootSheet->CountSheets();
+    *maxPage = *selPageTo   = m_parent->Schematic().Root().CountSheets();
 }
 
 
 bool SCH_PRINTOUT::HasPage( int pageNum )
 {
-    return g_RootSheet->CountSheets() >= pageNum;
+    return m_parent->Schematic().Root().CountSheets() >= pageNum;
 }
 
 
diff --git a/eeschema/dialogs/dialog_sch_import_settings.cpp b/eeschema/dialogs/dialog_sch_import_settings.cpp
index 88a56f672d..0cf5b11129 100644
--- a/eeschema/dialogs/dialog_sch_import_settings.cpp
+++ b/eeschema/dialogs/dialog_sch_import_settings.cpp
@@ -25,6 +25,7 @@
 #include <sch_edit_frame.h>
 #include <wildcards_and_files_ext.h>
 #include <confirm.h>
+#include <schematic.h>
 
 #include <dialog_sch_import_settings.h>
 
@@ -54,7 +55,7 @@ bool DIALOG_SCH_IMPORT_SETTINGS::TransferDataToWindow()
 
 void DIALOG_SCH_IMPORT_SETTINGS::OnBrowseClicked( wxCommandEvent& event )
 {
-    wxFileName fn = g_RootSheet->GetFileName();
+    wxFileName fn = m_frame->Schematic().Root().GetFileName();
     fn.SetExt( ProjectFileExtension );
 
     wxFileDialog dlg( this, _( "Import Settings From" ), fn.GetPath(), fn.GetFullName(),
diff --git a/eeschema/dialogs/dialog_sch_sheet_props.cpp b/eeschema/dialogs/dialog_sch_sheet_props.cpp
index fefcb30df2..6310677236 100644
--- a/eeschema/dialogs/dialog_sch_sheet_props.cpp
+++ b/eeschema/dialogs/dialog_sch_sheet_props.cpp
@@ -32,6 +32,7 @@
 #include <widgets/tab_traversal.h>
 #include <sch_edit_frame.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 #include <bitmaps.h>
 #include <eeschema_settings.h>
 #include <settings/color_settings.h>
@@ -168,7 +169,7 @@ bool DIALOG_SCH_SHEET_PROPS::TransferDataToWindow()
     m_backgroundSwatch->SetSwatchBackground( canvas );
 
     // set up the read-only fields
-    m_heirarchyPath->SetValue( g_CurrentSheet->PathHumanReadable() );
+    m_heirarchyPath->SetValue( m_frame->GetCurrentSheet().PathHumanReadable() );
     m_textCtrlTimeStamp->SetValue( m_sheet->m_Uuid.AsString() );
 
     Layout();
@@ -356,7 +357,7 @@ bool DIALOG_SCH_SHEET_PROPS::onSheetFilenameChanged( const wxString& aNewFilenam
 
     if( !fileName.IsAbsolute() )
     {
-        const SCH_SCREEN* currentScreen = g_CurrentSheet->LastScreen();
+        const SCH_SCREEN* currentScreen = m_frame->GetCurrentSheet().LastScreen();
         wxCHECK_MSG( currentScreen, false, "Invalid sheet path object." );
 
         wxFileName currentSheetFileName = currentScreen->GetFileName();
@@ -382,7 +383,7 @@ bool DIALOG_SCH_SHEET_PROPS::onSheetFilenameChanged( const wxString& aNewFilenam
 
     // Search for a schematic file having the same filename already in use in the hierarchy
     // or on disk, in order to reuse it.
-    if( !g_RootSheet->SearchHierarchy( newAbsoluteFilename, &useScreen ) )
+    if( !m_frame->Schematic().Root().SearchHierarchy( newAbsoluteFilename, &useScreen ) )
     {
         loadFromFile = wxFileExists( newAbsoluteFilename );
 
@@ -521,6 +522,7 @@ bool DIALOG_SCH_SHEET_PROPS::onSheetFilenameChanged( const wxString& aNewFilenam
     }
 
     wxFileName nativeFileName( aNewFilename );
+    SCH_SHEET_PATH& currentSheet = m_frame->GetCurrentSheet();
 
     if( useScreen )
     {
@@ -531,10 +533,10 @@ bool DIALOG_SCH_SHEET_PROPS::onSheetFilenameChanged( const wxString& aNewFilenam
         tmpSheet->SetScreen( useScreen );
 
         // No need to check for valid library IDs if we are using an existing screen.
-        if( m_frame->CheckSheetForRecursion( tmpSheet.get(), g_CurrentSheet ) )
+        if( m_frame->CheckSheetForRecursion( tmpSheet.get(), &currentSheet ) )
         {
             if( restoreSheet )
-                g_CurrentSheet->LastScreen()->Append( m_sheet );
+                currentSheet.LastScreen()->Append( m_sheet );
 
             return false;
         }
@@ -549,20 +551,20 @@ bool DIALOG_SCH_SHEET_PROPS::onSheetFilenameChanged( const wxString& aNewFilenam
             // Temporarily remove the sheet from the current schematic page so that recursion
             // and symbol library link tests can be performed with the modified sheet settings.
             restoreSheet = true;
-            g_CurrentSheet->LastScreen()->Remove( m_sheet );
+            currentSheet.LastScreen()->Remove( m_sheet );
         }
 
-        if( !m_frame->LoadSheetFromFile( m_sheet, g_CurrentSheet, newAbsoluteFilename )
-                || m_frame->CheckSheetForRecursion( m_sheet, g_CurrentSheet ) )
+        if( !m_frame->LoadSheetFromFile( m_sheet, &currentSheet, newAbsoluteFilename )
+                || m_frame->CheckSheetForRecursion( m_sheet, &currentSheet ) )
         {
             if( restoreSheet )
-                g_CurrentSheet->LastScreen()->Append( m_sheet );
+                currentSheet.LastScreen()->Append( m_sheet );
 
             return false;
         }
 
         if( restoreSheet )
-            g_CurrentSheet->LastScreen()->Append( m_sheet );
+            currentSheet.LastScreen()->Append( m_sheet );
     }
 
     if( m_clearAnnotationNewItems )
diff --git a/eeschema/dialogs/dialog_schematic_setup.cpp b/eeschema/dialogs/dialog_schematic_setup.cpp
index f8e877a6dc..94ba937956 100644
--- a/eeschema/dialogs/dialog_schematic_setup.cpp
+++ b/eeschema/dialogs/dialog_schematic_setup.cpp
@@ -18,6 +18,7 @@
  */
 
 #include <sch_edit_frame.h>
+#include <schematic.h>
 #include <kiface_i.h>
 #include <dialog_sch_import_settings.h>
 #include <panel_setup_severities.h>
@@ -41,8 +42,9 @@ DIALOG_SCHEMATIC_SETUP::DIALOG_SCHEMATIC_SETUP( SCH_EDIT_FRAME* aFrame ) :
     m_pinMap = new PANEL_SETUP_PINMAP( m_treebook, aFrame );
 
     ERC_ITEM dummyItem( 0 );
-    m_severities = new PANEL_SETUP_SEVERITIES( this, dummyItem, g_ErcSettings->m_Severities,
-                                               ERCE_FIRST, ERCE_LAST, ERCE_PIN_TO_PIN_WARNING );
+    m_severities = new PANEL_SETUP_SEVERITIES( this, dummyItem,
+            m_frame->Schematic().ErcSettings()->m_Severities, ERCE_FIRST, ERCE_LAST,
+            ERCE_PIN_TO_PIN_WARNING );
 
     m_textVars = new PANEL_TEXT_VARIABLES( m_treebook, &Prj() );
 
diff --git a/eeschema/dialogs/dialog_symbol_remap.cpp b/eeschema/dialogs/dialog_symbol_remap.cpp
index f078d25179..1172249773 100644
--- a/eeschema/dialogs/dialog_symbol_remap.cpp
+++ b/eeschema/dialogs/dialog_symbol_remap.cpp
@@ -35,10 +35,10 @@
 #include <lib_view_frame.h>
 #include <project_rescue.h>
 #include <sch_io_mgr.h>
-#include <sch_sheet.h>
 #include <sch_component.h>
 #include <sch_screen.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 #include <symbol_lib_table.h>
 #include <env_paths.h>
 
@@ -46,7 +46,8 @@
 
 
 DIALOG_SYMBOL_REMAP::DIALOG_SYMBOL_REMAP( SCH_EDIT_FRAME* aParent ) :
-    DIALOG_SYMBOL_REMAP_BASE( aParent )
+    DIALOG_SYMBOL_REMAP_BASE( aParent ),
+    m_frame( aParent )
 {
     m_remapped = false;
 
@@ -87,7 +88,8 @@ void DIALOG_SYMBOL_REMAP::OnRemapSymbols( wxCommandEvent& aEvent )
     // Ignore the never show rescue setting for one last rescue of legacy symbol
     // libraries before remapping to the symbol library table.  This ensures the
     // best remapping results.
-    LEGACY_RESCUER rescuer( Prj(), &parent->GetCurrentSheet(), parent->GetCanvas()->GetBackend() );
+    LEGACY_RESCUER rescuer( Prj(), &parent->Schematic(), &parent->GetCurrentSheet(),
+            parent->GetCanvas()->GetBackend() );
 
     if( RESCUER::RescueProject( this, rescuer, false ) )
     {
@@ -241,7 +243,7 @@ void DIALOG_SYMBOL_REMAP::createProjectSymbolLibTable( REPORTER& aReporter )
 void DIALOG_SYMBOL_REMAP::remapSymbolsToLibTable( REPORTER& aReporter )
 {
     wxString msg;
-    SCH_SCREENS schematic;
+    SCH_SCREENS schematic( m_frame->Schematic().Root() );
     SCH_COMPONENT* symbol;
     SCH_SCREEN* screen;
 
@@ -327,7 +329,7 @@ bool DIALOG_SYMBOL_REMAP::backupProject( REPORTER& aReporter )
     wxFileName srcFileName;
     wxFileName destFileName;
     wxFileName backupPath;
-    SCH_SCREENS schematic;
+    SCH_SCREENS schematic( m_frame->Schematic().Root() );
 
     // Copy backup files to different folder so as not to pollute the project folder.
     destFileName.SetPath( Prj().GetProjectPath() );
diff --git a/eeschema/dialogs/dialog_symbol_remap.h b/eeschema/dialogs/dialog_symbol_remap.h
index c21bce6e55..6f33345b41 100644
--- a/eeschema/dialogs/dialog_symbol_remap.h
+++ b/eeschema/dialogs/dialog_symbol_remap.h
@@ -87,6 +87,8 @@ private:
     bool backupProject( REPORTER& aReporter );
 
     bool m_remapped;
+
+    SCH_EDIT_FRAME* m_frame;
 };
 
 #endif  // _DIALOG_SYMBOL_REMAP_H_
diff --git a/eeschema/dialogs/dialog_update_from_pcb.cpp b/eeschema/dialogs/dialog_update_from_pcb.cpp
index 55008b5fd2..054794b3c3 100644
--- a/eeschema/dialogs/dialog_update_from_pcb.cpp
+++ b/eeschema/dialogs/dialog_update_from_pcb.cpp
@@ -123,7 +123,7 @@ void DIALOG_UPDATE_FROM_PCB::OnUpdateClick( wxCommandEvent& event )
 
     if( backAnno.FetchNetlistFromPCB( netlist ) && backAnno.BackAnnotateSymbols( netlist ) )
     {
-        g_CurrentSheet->UpdateAllScreenReferences();
+        m_frame->GetCurrentSheet().UpdateAllScreenReferences();
         m_frame->SetSheetNumberAndCount();
         m_frame->SyncView();
         m_frame->OnModify();
diff --git a/eeschema/eeschema_config.cpp b/eeschema/eeschema_config.cpp
index cf6acd53e0..3ab75d98b6 100644
--- a/eeschema/eeschema_config.cpp
+++ b/eeschema/eeschema_config.cpp
@@ -42,6 +42,7 @@
 #include <sch_edit_frame.h>
 #include <sch_junction.h>
 #include <sch_painter.h>
+#include <schematic.h>
 #include <settings/app_settings.h>
 #include <settings/settings_manager.h>
 #include <symbol_lib_table.h>
@@ -207,35 +208,6 @@ public:
 };
 
 
-int GetSeverity( int aErrorCode )
-{
-    // Special-case pin-to-pin errors:
-    // Ignore-or-not is controlled by ERCE_PIN_TO_PIN_WARNING (for both)
-    // Warning-or-error is controlled by which errorCode it is
-    if( aErrorCode == ERCE_PIN_TO_PIN_ERROR )
-    {
-        if( g_ErcSettings->m_Severities[ ERCE_PIN_TO_PIN_WARNING ] == RPT_SEVERITY_IGNORE )
-            return RPT_SEVERITY_IGNORE;
-        else
-            return RPT_SEVERITY_ERROR;
-    }
-    else if( aErrorCode == ERCE_PIN_TO_PIN_WARNING )
-    {
-        if( g_ErcSettings->m_Severities[ ERCE_PIN_TO_PIN_WARNING ] == RPT_SEVERITY_IGNORE )
-            return RPT_SEVERITY_IGNORE;
-        else
-            return RPT_SEVERITY_WARNING;
-    }
-
-    return g_ErcSettings->m_Severities[ aErrorCode ];
-}
-
-void SetSeverity( int aErrorCode, int aSeverity )
-{
-    g_ErcSettings->m_Severities[ aErrorCode ] = aSeverity;
-}
-
-
 /// Helper for all the old plotting/printing code while it still exists
 COLOR4D GetLayerColor( SCH_LAYER_ID aLayer )
 {
@@ -327,7 +299,7 @@ std::vector<PARAM_CFG*>& SCH_EDIT_FRAME::GetProjectFileParameters()
 
     params.push_back( new PARAM_CFG_FIELDNAMES( &m_templateFieldNames ) );
 
-    params.push_back( new PARAM_CFG_SEVERITIES( g_ErcSettings ) );
+    params.push_back( new PARAM_CFG_SEVERITIES( Schematic().ErcSettings() ) );
 
     return params;
 }
@@ -393,7 +365,7 @@ void SCH_EDIT_FRAME::DoShowSchematicSetupDialog( const wxString& aInitialPage,
 void SCH_EDIT_FRAME::SaveProjectSettings()
 {
     PROJECT&        prj = Prj();
-    wxFileName      fn = g_RootSheet->GetScreen()->GetFileName();  //ConfigFileName
+    wxFileName      fn = Schematic().RootScreen()->GetFileName();  //ConfigFileName
 
     fn.SetExt( ProjectFileExtension );
 
diff --git a/eeschema/erc.cpp b/eeschema/erc.cpp
index de6fa77eaf..ac23cbb6cb 100644
--- a/eeschema/erc.cpp
+++ b/eeschema/erc.cpp
@@ -38,6 +38,7 @@
 #include <sch_marker.h>
 #include <sch_sheet.h>
 #include <sch_reference_list.h>
+#include <schematic.h>
 #include <wx/ffile.h>
 
 
@@ -154,11 +155,12 @@ static int MinimalReq[ELECTRICAL_PINTYPES_TOTAL][ELECTRICAL_PINTYPES_TOTAL] =
 };
 
 
-int TestDuplicateSheetNames( bool aCreateMarker )
+int TestDuplicateSheetNames( SCHEMATIC* aSchematic, bool aCreateMarker )
 {
     SCH_SCREEN* screen;
     int         err_count = 0;
-    SCH_SCREENS screenList;      // Created the list of screen
+
+    SCH_SCREENS screenList( aSchematic->Root() );
 
     for( screen = screenList.GetFirst(); screen != NULL; screen = screenList.GetNext() )
     {
@@ -199,9 +201,9 @@ int TestDuplicateSheetNames( bool aCreateMarker )
 }
 
 
-void TestTextVars()
+void TestTextVars( SCHEMATIC* aSchematic )
 {
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( aSchematic->Root() );
 
     for( SCH_SCREEN* screen = screens.GetFirst(); screen != NULL; screen = screens.GetNext() )
     {
@@ -271,11 +273,12 @@ void TestTextVars()
 }
 
 
-int TestConflictingBusAliases()
+int TestConflictingBusAliases( SCHEMATIC* aSchematic )
 {
     wxString    msg;
     int         err_count = 0;
-    SCH_SCREENS screens;
+
+    SCH_SCREENS screens( aSchematic->Root() );
     std::vector< std::shared_ptr<BUS_ALIAS> > aliases;
 
     for( SCH_SCREEN* screen = screens.GetFirst(); screen != NULL; screen = screens.GetNext() )
@@ -311,7 +314,7 @@ int TestConflictingBusAliases()
 }
 
 
-int TestMultiunitFootprints( SCH_SHEET_LIST& aSheetList )
+int TestMultiunitFootprints( const SCH_SHEET_LIST& aSheetList )
 {
     int errors = 0;
     std::map<wxString, LIB_ID> footprints;
diff --git a/eeschema/erc.h b/eeschema/erc.h
index 517143f593..951d8c1f02 100644
--- a/eeschema/erc.h
+++ b/eeschema/erc.h
@@ -34,6 +34,7 @@
 class NETLIST_OBJECT;
 class NETLIST_OBJECT_LIST;
 class SCH_SHEET_LIST;
+class SCHEMATIC;
 
 /* For ERC markers: error types (used in diags, and to set the color):
 */
@@ -115,13 +116,13 @@ void TestOthersItems( NETLIST_OBJECT_LIST* aList, unsigned aNetItemRef, unsigned
  * @param aCreateMarker: true = create error markers in schematic,
  *                       false = calculate error count only
  */
-int TestDuplicateSheetNames( bool aCreateMarker );
+int TestDuplicateSheetNames( SCHEMATIC* aSchematic, bool aCreateMarker );
 
 /**
  * Function TestTextVars()
  * Checks for any unresolved text variable references.
  */
-void TestTextVars();
+void TestTextVars( SCHEMATIC* aSchematic );
 
 /**
  * Checks that there are not conflicting bus alias definitions in the schematic
@@ -131,14 +132,14 @@ void TestTextVars();
  *
  * @return the error count
  */
-int TestConflictingBusAliases();
+int TestConflictingBusAliases( SCHEMATIC* aSchematic );
 
 /**
  * Test if all units of each multiunit component have the same footprint assigned.
  * @param aSheetList contains components to be validated.
  * @return The error count.
  */
-int TestMultiunitFootprints( SCH_SHEET_LIST& aSheetList );
+int TestMultiunitFootprints( const SCH_SHEET_LIST& aSheetList );
 
 
 #endif  // _ERC_H
diff --git a/eeschema/files-io.cpp b/eeschema/files-io.cpp
index a8ac2a23a8..f1b82451db 100644
--- a/eeschema/files-io.cpp
+++ b/eeschema/files-io.cpp
@@ -40,6 +40,7 @@
 #include <sch_sheet.h>
 #include <sch_sheet_path.h>
 #include <sch_component.h>
+#include <schematic.h>
 #include <wildcards_and_files_ext.h>
 #include <project_rescue.h>
 #include <eeschema_config.h>
@@ -258,18 +259,11 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
     // unload current project file before loading new
     {
         SetScreen( nullptr );
-        delete g_RootSheet;
-
-        if( g_CurrentSheet )
-            g_CurrentSheet->clear();
-
-        g_RootSheet = nullptr;
-
         CreateScreens();
     }
 
     GetScreen()->SetFileName( fullFileName );
-    g_RootSheet->SetFileName( fullFileName );
+    Schematic().Root().SetFileName( fullFileName );
 
     SetStatusText( wxEmptyString );
     ClearMsgPanel();
@@ -323,8 +317,7 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
     else
     {
         SetScreen( nullptr );
-        delete g_RootSheet;   // Delete the current project.
-        g_RootSheet = NULL;   // Force CreateScreens() to build new empty project on load failure.
+        Schematic().Reset();
 
         SCH_PLUGIN* plugin = SCH_IO_MGR::FindPlugin( schFileType );
         SCH_PLUGIN::SCH_PLUGIN_RELEASER pi( plugin );
@@ -334,11 +327,9 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
 
         try
         {
-            g_RootSheet = pi->Load( fullFileName, &Kiway() );
+            Schematic().SetRoot( pi->Load( fullFileName, &Kiway(), &Schematic() ) );
 
-            g_CurrentSheet = new SCH_SHEET_PATH();
-            g_CurrentSheet->clear();
-            g_CurrentSheet->push_back( g_RootSheet );
+            GetCurrentSheet().push_back( &Schematic().Root() );
 
             if( !pi->GetError().IsEmpty() )
             {
@@ -368,7 +359,7 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
 
         // It's possible the schematic parser fixed errors due to bugs so warn the user
         // that the schematic has been fixed (modified).
-        SCH_SHEET_LIST sheetList( g_RootSheet );
+        SCH_SHEET_LIST sheetList = Schematic().GetSheets();
 
         if( sheetList.IsModified() )
         {
@@ -381,7 +372,7 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
 
         UpdateFileHistory( fullFileName );
 
-        SCH_SCREENS schematic;
+        SCH_SCREENS schematic( Schematic().Root() );
 
         // LIB_ID checks and symbol rescue only apply to the legacy file formats.
         if( schFileType == SCH_IO_MGR::SCH_LEGACY )
@@ -464,16 +455,16 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
                 screen->UpdateLocalLibSymbolLinks();
 
             // Restore all of the loaded symbol instances from the root sheet screen.
-            sheetList.UpdateSymbolInstances( g_RootSheet->GetScreen()->m_symbolInstances );
+            sheetList.UpdateSymbolInstances( Schematic().RootScreen()->m_symbolInstances );
         }
 
-        g_ConnectionGraph->Reset();
+        Schematic().ConnectionGraph()->Reset();
 
-        SetScreen( g_CurrentSheet->LastScreen() );
+        SetScreen( GetCurrentSheet().LastScreen() );
 
         // Migrate conflicting bus definitions
         // TODO(JE) This should only run once based on schematic file version
-        if( g_ConnectionGraph->GetBusesNeedingMigration().size() > 0 )
+        if( Schematic().ConnectionGraph()->GetBusesNeedingMigration().size() > 0 )
         {
             DIALOG_MIGRATE_BUSES dlg( this );
             dlg.ShowQuasiModal();
@@ -603,12 +594,12 @@ bool SCH_EDIT_FRAME::SaveProject()
 {
     wxString msg;
     SCH_SCREEN* screen;
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( Schematic().Root() );
     bool success = true;
     bool updateFileType = false;
 
     // I want to see it in the debugger, show me the string!  Can't do that with wxFileName.
-    wxString    fileName = Prj().AbsolutePath( g_RootSheet->GetFileName() );
+    wxString    fileName = Prj().AbsolutePath( Schematic().Root().GetFileName() );
     wxFileName  fn = fileName;
 
     if( !fn.IsDirWritable() )
@@ -697,7 +688,7 @@ bool SCH_EDIT_FRAME::SaveProject()
     }
 
     if( updateFileType )
-        UpdateFileHistory( g_RootSheet->GetScreen()->GetFileName() );
+        UpdateFileHistory( Schematic().RootScreen()->GetFileName() );
 
     // Save the sheet name map to the project file
     wxString      configFile = Prj().GetProjectFullName();
@@ -707,9 +698,7 @@ bool SCH_EDIT_FRAME::SaveProject()
     config->DeleteGroup( GROUP_SHEET_NAMES );
     config->SetPath( GROUP_SHEET_NAMES );
 
-    SCH_SHEET_LIST  sheetList( g_RootSheet );
-
-    for( SCH_SHEET_PATH& sheetPath : sheetList )
+    for( SCH_SHEET_PATH& sheetPath : Schematic().GetSheets() )
     {
         SCH_SHEET* sheet = sheetPath.Last();
         config->Write( wxString::Format( "%d", index++ ),
@@ -727,10 +716,10 @@ bool SCH_EDIT_FRAME::SaveProject()
 
 bool SCH_EDIT_FRAME::doAutoSave()
 {
-    wxFileName  tmpFileName = g_RootSheet->GetFileName();
+    wxFileName  tmpFileName = Schematic().Root().GetFileName();
     wxFileName  fn = tmpFileName;
     wxFileName  tmp;
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( Schematic().Root() );
 
     bool autoSaveOk = true;
 
@@ -773,7 +762,7 @@ bool SCH_EDIT_FRAME::doAutoSave()
 bool SCH_EDIT_FRAME::importFile( const wxString& aFileName, int aFileType )
 {
     wxFileName newfilename;
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = Schematic().GetSheets();
 
     switch( (SCH_IO_MGR::SCH_FILE_T) aFileType )
     {
@@ -792,10 +781,10 @@ bool SCH_EDIT_FRAME::importFile( const wxString& aFileName, int aFileType )
 
         try
         {
-            delete g_RootSheet;
-            g_RootSheet = nullptr;
+            Schematic().Reset();
+
             SCH_PLUGIN::SCH_PLUGIN_RELEASER pi( SCH_IO_MGR::FindPlugin( SCH_IO_MGR::SCH_EAGLE ) );
-            g_RootSheet = pi->Load( aFileName, &Kiway() );
+            Schematic().SetRoot( pi->Load( aFileName, &Kiway(), &Schematic() ) );
 
             // Eagle sheets do not use a worksheet frame by default, so set it to an empty one
             WS_DATA_MODEL& pglayout = WS_DATA_MODEL::GetTheInstance();
@@ -815,23 +804,21 @@ bool SCH_EDIT_FRAME::importFile( const wxString& aFileName, int aFileType )
             newfilename.SetName( Prj().GetProjectName() );
             newfilename.SetExt( LegacySchematicFileExtension );
 
-            g_CurrentSheet->clear();
-            g_CurrentSheet->push_back( g_RootSheet );
-            SetScreen( g_CurrentSheet->LastScreen() );
+            GetCurrentSheet().push_back( &Schematic().Root() );
+            SetScreen( GetCurrentSheet().LastScreen() );
 
-            g_RootSheet->SetFileName( newfilename.GetFullPath() );
+            Schematic().Root().SetFileName( newfilename.GetFullPath() );
             GetScreen()->SetFileName( newfilename.GetFullPath() );
             GetScreen()->SetModify();
             SaveProjectSettings();
 
             UpdateFileHistory( aFileName );
-            SCH_SCREENS schematic;
+            SCH_SCREENS schematic( Schematic().Root() );
             schematic.UpdateSymbolLinks();      // Update all symbol library links for all sheets.
 
             GetScreen()->m_Initialized = true;
-            SCH_SCREENS allScreens;
 
-            for( SCH_SCREEN* screen = allScreens.GetFirst(); screen; screen = allScreens.GetNext() )
+            for( SCH_SCREEN* screen = schematic.GetFirst(); screen; screen = schematic.GetNext() )
             {
                 for( auto item : screen->Items().OfType( SCH_COMPONENT_T ) )
                 {
@@ -888,7 +875,7 @@ bool SCH_EDIT_FRAME::importFile( const wxString& aFileName, int aFileType )
 
 bool SCH_EDIT_FRAME::AskToSaveChanges()
 {
-    SCH_SCREENS screenList;
+    SCH_SCREENS screenList( Schematic().Root() );
 
     // Save any currently open and modified project files.
     for( SCH_SCREEN* screen = screenList.GetFirst(); screen; screen = screenList.GetNext() )
diff --git a/eeschema/general.h b/eeschema/general.h
index fc247552ab..77afc598af 100644
--- a/eeschema/general.h
+++ b/eeschema/general.h
@@ -27,15 +27,10 @@
 
 #include <gal/color4d.h>
 #include <layers_id_colors_and_visibility.h>
-#include <erc_settings.h>
 
 using KIGFX::COLOR4D;
 
-class CONNECTION_GRAPH;
 class TRANSFORM;
-class SCH_SHEET;
-class SCH_SHEET_PATH;
-class ERC_SETTINGS;
 
 #define EESCHEMA_VERSION 5
 #define SCHEMATIC_HEAD_STRING "Schematic File Version"
@@ -48,27 +43,4 @@ class ERC_SETTINGS;
  */
 extern TRANSFORM DefaultTransform;
 
-/* First and main (root) screen */
-extern SCH_SHEET*   g_RootSheet;
-
-/**
- * With the new connectivity algorithm, many more places than before want to
- * know what the current sheet is.  This was moved here from SCH_EDIT_FRAME
- * but we could refactor things to get rid of this global.
- */
-extern SCH_SHEET_PATH* g_CurrentSheet;    ///< which sheet we are presently working on.
-
-/**
- * This also wants to live in the eventual SCHEMATIC object
- */
-extern CONNECTION_GRAPH* g_ConnectionGraph;
-
-/**
- * This also wants to live in the eventual SCHEMATIC object
- */
-extern ERC_SETTINGS* g_ErcSettings;
-
-int GetSeverity( int aErrorCode );
-void SetSeverity( int aErrorCode, int aSeverity );
-
 #endif    // _GENERAL_H_
diff --git a/eeschema/getpart.cpp b/eeschema/getpart.cpp
index 07f8677990..92127b3693 100644
--- a/eeschema/getpart.cpp
+++ b/eeschema/getpart.cpp
@@ -214,7 +214,7 @@ void SCH_EDIT_FRAME::SelectUnit( SCH_COMPONENT* aComponent, int aUnit )
         SaveCopyInUndoList( aComponent, UR_CHANGED );
 
     /* Update the unit number. */
-    aComponent->SetUnitSelection( g_CurrentSheet, aUnit );
+    aComponent->SetUnitSelection( &GetCurrentSheet(), aUnit );
     aComponent->SetUnit( aUnit );
     aComponent->ClearFlags();
     aComponent->SetFlags( savedFlags ); // Restore m_Flag modified by SetUnit()
diff --git a/eeschema/hierarch.cpp b/eeschema/hierarch.cpp
index 5527a625fa..39004578ff 100644
--- a/eeschema/hierarch.cpp
+++ b/eeschema/hierarch.cpp
@@ -33,6 +33,7 @@
 #include <general.h>
 #include <sch_sheet.h>
 #include <sch_sheet_path.h>
+#include <schematic.h>
 #include <wx/imaglist.h>
 #include <wx/treectrl.h>
 #include <tool/tool_manager.h>
@@ -95,10 +96,10 @@ HIERARCHY_NAVIG_DLG::HIERARCHY_NAVIG_DLG( SCH_EDIT_FRAME* aParent ) :
     wxTreeItemId root = m_Tree->AddRoot( _( "Root" ), 0, 1 );
     m_Tree->SetItemBold( root, true );
 
-    m_list.push_back( g_RootSheet );
+    m_list.push_back( &m_SchFrameEditor->Schematic().Root() );
     m_Tree->SetItemData( root, new TreeItemData( m_list ) );
 
-    if( m_SchFrameEditor->GetCurrentSheet().Last() == g_RootSheet )
+    if( m_SchFrameEditor->GetCurrentSheet().Last() == &m_SchFrameEditor->Schematic().Root() )
         m_Tree->SelectItem( root );
 
     buildHierarchyTree( &m_list, &root );
@@ -195,7 +196,7 @@ void HIERARCHY_NAVIG_DLG::UpdateHierarchyTree()
     wxTreeItemId root = m_Tree->GetRootItem();
     m_Tree->DeleteChildren( root );
     m_list.clear();
-    m_list.push_back( g_RootSheet );
+    m_list.push_back( &m_SchFrameEditor->Schematic().Root() );
     buildHierarchyTree( &m_list, &root );
 
     Thaw();
@@ -230,7 +231,7 @@ void SCH_EDIT_FRAME::DisplayCurrentSheet()
     m_toolManager->RunAction( ACTIONS::cancelInteractive, true );
     m_toolManager->RunAction( EE_ACTIONS::clearSelection, true );
 
-    SCH_SCREEN* screen = g_CurrentSheet->LastScreen();
+    SCH_SCREEN* screen = GetCurrentSheet().LastScreen();
 
     wxASSERT( screen );
 
@@ -240,7 +241,7 @@ void SCH_EDIT_FRAME::DisplayCurrentSheet()
     GetScreen()->SetGrid( m_LastGridSizeId + ID_POPUP_GRID_LEVEL_1000 );
 
     // update the References
-    g_CurrentSheet->UpdateAllScreenReferences();
+    GetCurrentSheet().UpdateAllScreenReferences();
     SetSheetNumberAndCount();
 
     if( !screen->m_Initialized )
diff --git a/eeschema/lib_pin.cpp b/eeschema/lib_pin.cpp
index 4413f105b2..dac616eb3a 100644
--- a/eeschema/lib_pin.cpp
+++ b/eeschema/lib_pin.cpp
@@ -48,6 +48,7 @@
 #include <lib_pin.h>
 #include <transform.h>
 #include <sch_component.h>
+#include <sch_edit_frame.h>  // For message panel debug info
 #include <sch_sheet_path.h>
 #include <settings/settings_manager.h>
 #include <settings/color_settings.h>
@@ -1482,7 +1483,12 @@ void LIB_PIN::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, std::vector<MSG_PANEL_ITE
 
 #if defined(DEBUG)
 
-    auto conn = aComponent->GetConnectionForPin( this, *g_CurrentSheet );
+    SCH_EDIT_FRAME* frame = dynamic_cast<SCH_EDIT_FRAME*>( aFrame );
+
+    if( !frame )
+        return;
+
+    auto conn = aComponent->GetConnectionForPin( this, frame->GetCurrentSheet() );
 
     if( conn )
         conn->AppendDebugInfoToMsgPanel( aList );
diff --git a/eeschema/libarch.cpp b/eeschema/libarch.cpp
index fc35077f9b..edd3d15d95 100644
--- a/eeschema/libarch.cpp
+++ b/eeschema/libarch.cpp
@@ -37,6 +37,7 @@
 #include <class_library.h>
 #include <sch_component.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 
 
 bool SCH_EDIT_FRAME::CreateArchiveLibraryCacheFile( bool aUseCurrentSheetFilename )
@@ -46,7 +47,7 @@ bool SCH_EDIT_FRAME::CreateArchiveLibraryCacheFile( bool aUseCurrentSheetFilenam
     if( aUseCurrentSheetFilename )
         fn = GetScreen()->GetFileName();
     else
-        fn = g_RootSheet->GetScreen()->GetFileName();
+        fn = Schematic().RootScreen()->GetFileName();
 
     fn.SetName( fn.GetName() + "-cache" );
     fn.SetExt( SchematicLibraryFileExtension );
@@ -55,7 +56,7 @@ bool SCH_EDIT_FRAME::CreateArchiveLibraryCacheFile( bool aUseCurrentSheetFilenam
 
     // Update the schematic symbol library links.
     // because the lib cache has changed
-    SCH_SCREENS schematic;
+    SCH_SCREENS schematic( Schematic().Root() );
     schematic.UpdateSymbolLinks();
 
     return success;
@@ -66,7 +67,7 @@ bool SCH_EDIT_FRAME::CreateArchiveLibrary( const wxString& aFileName )
 {
     wxString          tmp;
     wxString          errorMsg;
-    SCH_SCREENS       screens;
+    SCH_SCREENS       screens( Schematic().Root() );
 
     // Create a new empty library to archive components:
     std::unique_ptr<PART_LIB> archLib( new PART_LIB( LIBRARY_TYPE_EESCHEMA, aFileName ) );
diff --git a/eeschema/menubar.cpp b/eeschema/menubar.cpp
index 971730aa42..7cb4d3320a 100644
--- a/eeschema/menubar.cpp
+++ b/eeschema/menubar.cpp
@@ -28,6 +28,7 @@
 #include <kiface_i.h>
 #include <menus_helpers.h>
 #include <pgm_base.h>
+#include <schematic.h>
 #include <tool/conditional_menu.h>
 #include <tool/tool_manager.h>
 #include <tools/ee_selection_tool.h>
@@ -46,10 +47,10 @@ void SCH_EDIT_FRAME::ReCreateMenuBar()
     wxMenuBar* oldMenuBar = GetMenuBar();
     wxMenuBar* menuBar = new wxMenuBar();
 
-    auto modifiedDocumentCondition = [] ( const SELECTION& sel ) {
-        SCH_SHEET_LIST sheetList( g_RootSheet );
-        return sheetList.IsModified();
-    };
+    auto modifiedDocumentCondition = [&]( const SELECTION& sel )
+                                     {
+                                         return Schematic().GetSheets().IsModified();
+                                     };
 
     //-- File menu -----------------------------------------------------------
     //
@@ -162,24 +163,40 @@ void SCH_EDIT_FRAME::ReCreateMenuBar()
     //
     CONDITIONAL_MENU* viewMenu = new CONDITIONAL_MENU( false, selTool );
 
-    auto belowRootSheetCondition = [] ( const SELECTION& aSel ) {
-        return g_CurrentSheet->Last() != g_RootSheet;
-    };
-    auto gridShownCondition = [ this ] ( const SELECTION& aSel ) {
-        return IsGridVisible();
-    };
-    auto imperialUnitsCondition = [this]( const SELECTION& aSel ) {
-        return GetUserUnits() == EDA_UNITS::INCHES;
-    };
-    auto metricUnitsCondition = [this]( const SELECTION& aSel ) {
-        return GetUserUnits() == EDA_UNITS::MILLIMETRES;
-    };
-    auto fullCrosshairCondition = [ this ] ( const SELECTION& aSel ) {
-        return GetGalDisplayOptions().m_fullscreenCursor;
-    };
-    auto hiddenPinsCondition = [ this ] ( const SELECTION& aSel ) {
-        return GetShowAllPins();
-    };
+    auto belowRootSheetCondition =
+            [this]( const SELECTION& aSel )
+            {
+                return GetCurrentSheet().Last() != &Schematic().Root();
+            };
+
+    auto gridShownCondition =
+            [this]( const SELECTION& aSel )
+            {
+                return IsGridVisible();
+            };
+
+    auto imperialUnitsCondition =
+            [this]( const SELECTION& aSel )
+            {
+                return GetUserUnits() == EDA_UNITS::INCHES;
+            };
+
+    auto metricUnitsCondition =
+            [this]( const SELECTION& aSel )
+            {
+                return GetUserUnits() == EDA_UNITS::MILLIMETRES;
+            };
+
+    auto fullCrosshairCondition =
+            [this]( const SELECTION& aSel )
+            {
+                return GetGalDisplayOptions().m_fullscreenCursor;
+            };
+    auto hiddenPinsCondition =
+            [this]( const SELECTION& aSel )
+            {
+                return GetShowAllPins();
+            };
 
     viewMenu->AddItem( ACTIONS::showSymbolBrowser,        EE_CONDITIONS::ShowAlways );
     viewMenu->AddItem( EE_ACTIONS::navigateHierarchy,     EE_CONDITIONS::ShowAlways );
@@ -256,12 +273,14 @@ void SCH_EDIT_FRAME::ReCreateMenuBar()
     //
     CONDITIONAL_MENU* toolsMenu = new CONDITIONAL_MENU( false, selTool );
 
-    auto remapSymbolsCondition = [] ( const SELECTION& aSel ) {
-        SCH_SCREENS schematic;
+    auto remapSymbolsCondition =
+            [&]( const SELECTION& aSel )
+            {
+                SCH_SCREENS schematic( Schematic().Root() );
 
-        // The remapping can only be performed on legacy projects.
-        return schematic.HasNoFullyDefinedLibIds();
-    };
+                // The remapping can only be performed on legacy projects.
+                return schematic.HasNoFullyDefinedLibIds();
+            };
 
     toolsMenu->AddItem( ACTIONS::updatePcbFromSchematic,    EE_CONDITIONS::ShowAlways );
     toolsMenu->AddItem( ACTIONS::updateSchematicFromPcb,    EE_CONDITIONS::ShowAlways );
diff --git a/eeschema/netlist_exporters/netlist_exporter.cpp b/eeschema/netlist_exporters/netlist_exporter.cpp
index 50cfdfb06c..1695900e1e 100644
--- a/eeschema/netlist_exporters/netlist_exporter.cpp
+++ b/eeschema/netlist_exporters/netlist_exporter.cpp
@@ -305,7 +305,7 @@ void NETLIST_EXPORTER::findAllUnitsOfComponent( SCH_COMPONENT* aComponent,
     wxString    ref = aComponent->GetRef( aSheetPath );
     wxString    ref2;
 
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
 
     for( unsigned i = 0;  i < sheetList.size();  i++ )
     {
diff --git a/eeschema/netlist_exporters/netlist_exporter.h b/eeschema/netlist_exporters/netlist_exporter.h
index 37674af89c..95e0711ae7 100644
--- a/eeschema/netlist_exporters/netlist_exporter.h
+++ b/eeschema/netlist_exporters/netlist_exporter.h
@@ -34,6 +34,7 @@
 #include <sch_component.h>
 #include <sch_text.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 
 /**
  * UNIQUE_STRINGS
@@ -102,6 +103,9 @@ protected:
     /// unique library parts used. LIB_PART items are sorted by names
     std::set<LIB_PART*, LIB_PART_LESS_THAN> m_LibParts;
 
+    /// The schematic we're generating a netlist for
+    SCHEMATIC* m_schematic;
+
     /**
      * Function sprintPinNetName
      * formats the net name for \a aPin using \a aNetNameFormat into \a aResult.
@@ -171,8 +175,9 @@ public:
      * @param aMasterList we take ownership of this here.
      * @param aLibTable is the symbol library table of the project.
      */
-    NETLIST_EXPORTER( NETLIST_OBJECT_LIST* aMasterList ) :
-        m_masterList( aMasterList )
+    NETLIST_EXPORTER( NETLIST_OBJECT_LIST* aMasterList, SCHEMATIC* aSchematic ) :
+        m_masterList( aMasterList ),
+        m_schematic( aSchematic )
     {
         wxASSERT( aMasterList );
     }
diff --git a/eeschema/netlist_exporters/netlist_exporter_cadstar.cpp b/eeschema/netlist_exporters/netlist_exporter_cadstar.cpp
index 7bc649ea1c..fec5f2c186 100644
--- a/eeschema/netlist_exporters/netlist_exporter_cadstar.cpp
+++ b/eeschema/netlist_exporters/netlist_exporter_cadstar.cpp
@@ -69,7 +69,7 @@ bool NETLIST_EXPORTER_CADSTAR::WriteNetlist( const wxString& aOutFileName, unsig
     // Create netlist module section
     m_ReferencesAlreadyFound.Clear();
 
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
 
     for( unsigned i = 0; i < sheetList.size(); i++ )
     {
diff --git a/eeschema/netlist_exporters/netlist_exporter_cadstar.h b/eeschema/netlist_exporters/netlist_exporter_cadstar.h
index ca67fb9792..620925c7ce 100644
--- a/eeschema/netlist_exporters/netlist_exporter_cadstar.h
+++ b/eeschema/netlist_exporters/netlist_exporter_cadstar.h
@@ -48,8 +48,8 @@ class NETLIST_EXPORTER_CADSTAR : public NETLIST_EXPORTER
     bool writeListOfNets( FILE* f );
 
 public:
-    NETLIST_EXPORTER_CADSTAR( NETLIST_OBJECT_LIST* aMasterList ) :
-        NETLIST_EXPORTER( aMasterList )
+    NETLIST_EXPORTER_CADSTAR( NETLIST_OBJECT_LIST* aMasterList, SCHEMATIC* aSchematic ) :
+        NETLIST_EXPORTER( aMasterList, aSchematic )
     {
     }
 
diff --git a/eeschema/netlist_exporters/netlist_exporter_generic.cpp b/eeschema/netlist_exporters/netlist_exporter_generic.cpp
index d9d523edde..4627121e43 100644
--- a/eeschema/netlist_exporters/netlist_exporter_generic.cpp
+++ b/eeschema/netlist_exporters/netlist_exporter_generic.cpp
@@ -106,7 +106,7 @@ void NETLIST_EXPORTER_GENERIC::addComponentFields( XNODE* xcomp, SCH_COMPONENT*
 
         wxString    ref = comp->GetRef( aSheet );
 
-        SCH_SHEET_LIST sheetList( g_RootSheet );
+        SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
         int minUnit = comp->GetUnit();
 
         for( unsigned i = 0;  i < sheetList.size();  i++ )
@@ -193,7 +193,6 @@ void NETLIST_EXPORTER_GENERIC::addComponentFields( XNODE* xcomp, SCH_COMPONENT*
             xfield->AddAttribute( "name", it->first );
         }
     }
-
 }
 
 
@@ -203,7 +202,7 @@ XNODE* NETLIST_EXPORTER_GENERIC::makeComponents()
 
     m_ReferencesAlreadyFound.Clear();
 
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
 
     // Output is xml, so there is no reason to remove spaces from the field values.
     // And XML element names need not be translated to various languages.
@@ -290,7 +289,7 @@ XNODE* NETLIST_EXPORTER_GENERIC::makeDesignHeader()
     wxFileName sourceFileName;
 
     // the root sheet is a special sheet, call it source
-    xdesign->AddChild( node( "source", g_RootSheet->GetScreen()->GetFileName() ) );
+    xdesign->AddChild( node( "source", m_schematic->GetFileName() ) );
 
     xdesign->AddChild( node( "date", DateAndTime() ) );
 
@@ -300,7 +299,7 @@ XNODE* NETLIST_EXPORTER_GENERIC::makeDesignHeader()
     /*
         Export the sheets information
     */
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
 
     for( unsigned i = 0;  i < sheetList.size();  i++ )
     {
diff --git a/eeschema/netlist_exporters/netlist_exporter_generic.h b/eeschema/netlist_exporters/netlist_exporter_generic.h
index 7ec1d01c72..5aebeadef3 100644
--- a/eeschema/netlist_exporters/netlist_exporter_generic.h
+++ b/eeschema/netlist_exporters/netlist_exporter_generic.h
@@ -70,8 +70,9 @@ protected:
 public:
     NETLIST_EXPORTER_GENERIC( SCH_EDIT_FRAME* aFrame,
                               NETLIST_OBJECT_LIST* aMasterList,
+                              SCHEMATIC* aSchematic,
                               CONNECTION_GRAPH* aGraph = nullptr  ) :
-        NETLIST_EXPORTER( aMasterList ),
+        NETLIST_EXPORTER( aMasterList, aSchematic ),
         m_libTable( aFrame->Prj().SchSymbolLibTable() ),
         m_graph( aGraph )
     {}
diff --git a/eeschema/netlist_exporters/netlist_exporter_kicad.h b/eeschema/netlist_exporters/netlist_exporter_kicad.h
index 27813d64e9..7ecdfe9ef8 100644
--- a/eeschema/netlist_exporters/netlist_exporter_kicad.h
+++ b/eeschema/netlist_exporters/netlist_exporter_kicad.h
@@ -40,8 +40,9 @@ class NETLIST_EXPORTER_KICAD : public NETLIST_EXPORTER_GENERIC
 public:
     NETLIST_EXPORTER_KICAD( SCH_EDIT_FRAME* aFrame,
                             NETLIST_OBJECT_LIST* aMasterList,
+                            SCHEMATIC* aSchematic,
                             CONNECTION_GRAPH* aGraph = nullptr ) :
-        NETLIST_EXPORTER_GENERIC( aFrame, aMasterList, aGraph )
+        NETLIST_EXPORTER_GENERIC( aFrame, aMasterList, aSchematic, aGraph )
     {}
 
     /**
diff --git a/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.cpp b/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.cpp
index 04f5f77241..7e9ce0936a 100644
--- a/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.cpp
+++ b/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.cpp
@@ -68,7 +68,7 @@ bool NETLIST_EXPORTER_ORCADPCB2::WriteNetlist( const wxString& aOutFileName,
     // Create netlist module section
     m_ReferencesAlreadyFound.Clear();
 
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
 
     for( unsigned i = 0;  i < sheetList.size();  i++ )
     {
diff --git a/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.h b/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.h
index 8b53b7d75c..c93849ec6d 100644
--- a/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.h
+++ b/eeschema/netlist_exporters/netlist_exporter_orcadpcb2.h
@@ -35,8 +35,8 @@
 class NETLIST_EXPORTER_ORCADPCB2 : public NETLIST_EXPORTER
 {
 public:
-    NETLIST_EXPORTER_ORCADPCB2( NETLIST_OBJECT_LIST* aMasterList ) :
-        NETLIST_EXPORTER( aMasterList )
+    NETLIST_EXPORTER_ORCADPCB2( NETLIST_OBJECT_LIST* aMasterList, SCHEMATIC* aSchematic ) :
+        NETLIST_EXPORTER( aMasterList, aSchematic )
     {
     }
 
diff --git a/eeschema/netlist_exporters/netlist_exporter_pspice.cpp b/eeschema/netlist_exporters/netlist_exporter_pspice.cpp
index 6735afeef9..917a38de05 100644
--- a/eeschema/netlist_exporters/netlist_exporter_pspice.cpp
+++ b/eeschema/netlist_exporters/netlist_exporter_pspice.cpp
@@ -267,7 +267,8 @@ wxString NETLIST_EXPORTER_PSPICE::GetSpiceFieldDefVal( SPICE_FIELD aField,
 bool NETLIST_EXPORTER_PSPICE::ProcessNetlist( unsigned aCtl )
 {
     const wxString      delimiters( "{:,; }" );
-    SCH_SHEET_LIST      sheetList( g_RootSheet );
+
+    SCH_SHEET_LIST      sheetList = m_schematic->GetSheets();
     // Set of reference names, to check for duplications
     std::set<wxString>  refNames;
 
@@ -378,7 +379,7 @@ bool NETLIST_EXPORTER_PSPICE::ProcessNetlist( unsigned aCtl )
 
 void NETLIST_EXPORTER_PSPICE::UpdateDirectives( unsigned aCtl )
 {
-    const SCH_SHEET_LIST& sheetList = g_RootSheet;
+    const SCH_SHEET_LIST& sheetList = m_schematic->GetSheets();
     wxRegEx couplingK( "^[kK][[:digit:]]*[[:space:]]+[[:alnum:]]+[[:space:]]+[[:alnum:]]+",
             wxRE_ADVANCED );
 
diff --git a/eeschema/netlist_exporters/netlist_exporter_pspice.h b/eeschema/netlist_exporters/netlist_exporter_pspice.h
index d651311fe4..0c163c1ac8 100644
--- a/eeschema/netlist_exporters/netlist_exporter_pspice.h
+++ b/eeschema/netlist_exporters/netlist_exporter_pspice.h
@@ -101,9 +101,10 @@ struct SPICE_ITEM
 class NETLIST_EXPORTER_PSPICE : public NETLIST_EXPORTER
 {
 public:
-    NETLIST_EXPORTER_PSPICE( NETLIST_OBJECT_LIST* aMasterList, PROJECT* aProject = NULL ) :
-        NETLIST_EXPORTER( aMasterList ),
-        m_project( aProject )
+    NETLIST_EXPORTER_PSPICE( NETLIST_OBJECT_LIST* aMasterList, SCHEMATIC* aSchematic,
+            PROJECT* aProject = nullptr ) :
+            NETLIST_EXPORTER( aMasterList, aSchematic ),
+            m_project( aProject )
     {
     }
 
diff --git a/eeschema/netlist_generator.cpp b/eeschema/netlist_generator.cpp
index fa55c60754..f0acd29570 100644
--- a/eeschema/netlist_generator.cpp
+++ b/eeschema/netlist_generator.cpp
@@ -33,6 +33,7 @@
 #include <gestfich.h>
 #include <pgm_base.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 #include <reporter.h>
 #include <confirm.h>
 #include <kiway.h>
@@ -61,22 +62,25 @@ bool SCH_EDIT_FRAME::WriteNetListFile( NETLIST_OBJECT_LIST* aConnectedItemsList,
 
     NETLIST_EXPORTER *helper;
 
+    SCHEMATIC* sch = &Schematic();
+
     switch( aFormat )
     {
     case NET_TYPE_PCBNEW:
-        helper = new NETLIST_EXPORTER_KICAD( this, aConnectedItemsList, g_ConnectionGraph );
+        helper = new NETLIST_EXPORTER_KICAD(
+                this, aConnectedItemsList, sch, sch->ConnectionGraph() );
         break;
 
     case NET_TYPE_ORCADPCB2:
-        helper = new NETLIST_EXPORTER_ORCADPCB2( aConnectedItemsList );
+        helper = new NETLIST_EXPORTER_ORCADPCB2( aConnectedItemsList, sch );
         break;
 
     case NET_TYPE_CADSTAR:
-        helper = new NETLIST_EXPORTER_CADSTAR( aConnectedItemsList );
+        helper = new NETLIST_EXPORTER_CADSTAR( aConnectedItemsList, sch );
         break;
 
     case NET_TYPE_SPICE:
-        helper = new NETLIST_EXPORTER_PSPICE( aConnectedItemsList );
+        helper = new NETLIST_EXPORTER_PSPICE( aConnectedItemsList, sch );
         break;
 
     default:
@@ -85,8 +89,8 @@ bool SCH_EDIT_FRAME::WriteNetListFile( NETLIST_OBJECT_LIST* aConnectedItemsList,
             tmpFile.SetExt( GENERIC_INTERMEDIATE_NETLIST_EXT );
             fileName = tmpFile.GetFullPath();
 
-            helper = new NETLIST_EXPORTER_GENERIC( this, aConnectedItemsList,
-                                                   g_ConnectionGraph );
+            helper = new NETLIST_EXPORTER_GENERIC( this, aConnectedItemsList, sch,
+                    sch->ConnectionGraph() );
             executeCommandLine = true;
         }
         break;
@@ -158,14 +162,13 @@ bool SCH_EDIT_FRAME::WriteNetListFile( NETLIST_OBJECT_LIST* aConnectedItemsList,
 
 
 //Imported function:
-int TestDuplicateSheetNames( bool aCreateMarker );
+int TestDuplicateSheetNames( SCHEMATIC* aSchematic, bool aCreateMarker );
 
 
 bool SCH_EDIT_FRAME::prepareForNetlist()
 {
     // Ensure all power symbols have a valid reference
-    SCH_SHEET_LIST sheets( g_RootSheet );
-    sheets.AnnotatePowerSymbols();
+    Schematic().GetSheets().AnnotatePowerSymbols();
 
     // Performs some controls:
     if( CheckAnnotate( NULL_REPORTER::GetInstance(), 0 ) )
@@ -178,7 +181,7 @@ bool SCH_EDIT_FRAME::prepareForNetlist()
     }
 
     // Test duplicate sheet names:
-    if( TestDuplicateSheetNames( false ) > 0 )
+    if( TestDuplicateSheetNames( &Schematic(), false ) > 0 )
     {
         if( !IsOK( this, _( "Error: duplicate sheet names. Continue?" ) ) )
             return false;
@@ -191,7 +194,7 @@ bool SCH_EDIT_FRAME::prepareForNetlist()
 void SCH_EDIT_FRAME::sendNetlistToCvpcb()
 {
     NETLIST_OBJECT_LIST*   net_atoms = BuildNetListBase();
-    NETLIST_EXPORTER_KICAD exporter( this, net_atoms, g_ConnectionGraph );
+    NETLIST_EXPORTER_KICAD exporter( this, net_atoms, &Schematic(), Schematic().ConnectionGraph() );
     STRING_FORMATTER       formatter;
 
     // @todo : trim GNL_ALL down to minimum for CVPCB
@@ -212,8 +215,7 @@ NETLIST_OBJECT_LIST* SCH_EDIT_FRAME::CreateNetlist( bool aSilent,
     }
     else // performs similar function as prepareForNetlist but without a dialog.
     {
-        SCH_SHEET_LIST sheets( g_RootSheet );
-        sheets.AnnotatePowerSymbols();
+        Schematic().GetSheets().AnnotatePowerSymbols();
 
         if( aSilentAnnotate )
             AnnotateComponents( true, UNSORTED, INCREMENTAL_BY_REF, 0, false, false, true,
@@ -236,7 +238,7 @@ NETLIST_OBJECT_LIST* SCH_EDIT_FRAME::BuildNetListBase( bool updateStatusText )
     std::unique_ptr<NETLIST_OBJECT_LIST> ret( new NETLIST_OBJECT_LIST() );
 
     // Creates the flattened sheet list:
-    SCH_SHEET_LIST aSheets( g_RootSheet );
+    SCH_SHEET_LIST aSheets = Schematic().GetSheets();
 
     // Build netlist info
     bool success = ret->BuildNetListInfo( aSheets );
diff --git a/eeschema/netlist_object.cpp b/eeschema/netlist_object.cpp
index 6cf9406336..17df2fdfb3 100644
--- a/eeschema/netlist_object.cpp
+++ b/eeschema/netlist_object.cpp
@@ -36,6 +36,7 @@
 #include <sch_connection.h>
 #include <netlist_object.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 
 #if defined(DEBUG)
 
@@ -242,7 +243,7 @@ void NETLIST_OBJECT::ConvertBusToNetListItems( NETLIST_OBJECT_LIST& aNetListItem
     // bus groups (including with nested vectors) the code is something arbitrary.
     long member_offset = 0;
 
-    auto alias = SCH_SCREEN::GetBusAlias( m_Label );
+    auto alias = static_cast<SCH_ITEM*>( m_Comp )->Schematic()->GetBusAlias( m_Label );
     wxString group_name;
     bool self_set = false;
     std::vector<wxString> bus_contents_vec;
@@ -286,7 +287,8 @@ void NETLIST_OBJECT::ConvertBusToNetListItems( NETLIST_OBJECT_LIST& aNetListItem
                 fillBusVector( aNetListItems, prefix, begin, end, member_offset );
                 member_offset += std::abs( end - begin );
             }
-            else if( auto nested_alias = SCH_SCREEN::GetBusAlias( bus_member ) )
+            else if( auto nested_alias = static_cast<SCH_ITEM*>( m_Comp )->Schematic()->GetBusAlias(
+                             bus_member ) )
             {
                 // Nested alias inside a group
                 for( const auto& alias_member : nested_alias->Members() )
diff --git a/eeschema/plot_schematic_DXF.cpp b/eeschema/plot_schematic_DXF.cpp
index 211989e397..a78d52c651 100644
--- a/eeschema/plot_schematic_DXF.cpp
+++ b/eeschema/plot_schematic_DXF.cpp
@@ -29,6 +29,7 @@
 #include <plotter.h>
 #include <sch_edit_frame.h>
 #include <sch_sheet_path.h>
+#include <schematic.h>
 #include <project.h>
 #include <pgm_base.h>
 #include <settings/settings_manager.h>
@@ -52,7 +53,7 @@ void DIALOG_PLOT_SCHEMATIC::CreateDXFFile( bool aPlotAll, bool aPlotFrameRef )
     SCH_SHEET_LIST sheetList;
 
     if( aPlotAll )
-        sheetList.BuildSheetList( g_RootSheet );
+        sheetList.BuildSheetList( &schframe->Schematic().Root() );
     else
         sheetList.push_back( schframe->GetCurrentSheet() );
 
diff --git a/eeschema/plot_schematic_HPGL.cpp b/eeschema/plot_schematic_HPGL.cpp
index 054f179aef..326e995e9c 100644
--- a/eeschema/plot_schematic_HPGL.cpp
+++ b/eeschema/plot_schematic_HPGL.cpp
@@ -30,6 +30,7 @@
 #include <sch_edit_frame.h>
 #include <base_units.h>
 #include <sch_sheet_path.h>
+#include <schematic.h>
 #include <project.h>
 #include <pgm_base.h>
 #include <settings/settings_manager.h>
@@ -98,7 +99,7 @@ void DIALOG_PLOT_SCHEMATIC::createHPGLFile( bool aPlotAll, bool aPlotFrameRef )
     SCH_SHEET_LIST  sheetList;
 
     if( aPlotAll )
-        sheetList.BuildSheetList( g_RootSheet );
+        sheetList.BuildSheetList( &m_parent->Schematic().Root() );
     else
         sheetList.push_back( m_parent->GetCurrentSheet() );
 
diff --git a/eeschema/plot_schematic_PDF.cpp b/eeschema/plot_schematic_PDF.cpp
index fbbc6813ee..b66ec5637a 100644
--- a/eeschema/plot_schematic_PDF.cpp
+++ b/eeschema/plot_schematic_PDF.cpp
@@ -31,6 +31,7 @@
 #include <base_units.h>
 #include <sch_sheet_path.h>
 #include <sch_painter.h>
+#include <schematic.h>
 #include <pgm_base.h>
 #include <project.h>
 #include <general.h>
@@ -56,7 +57,7 @@ void DIALOG_PLOT_SCHEMATIC::createPDFFile( bool aPlotAll, bool aPlotFrameRef,
     SCH_SHEET_LIST sheetList;
 
     if( aPlotAll )
-        sheetList.BuildSheetList( g_RootSheet );
+        sheetList.BuildSheetList( &m_parent->Schematic().Root() );
     else
         sheetList.push_back( m_parent->GetCurrentSheet() );
 
diff --git a/eeschema/plot_schematic_PS.cpp b/eeschema/plot_schematic_PS.cpp
index 84b7101999..3c0bc4b536 100644
--- a/eeschema/plot_schematic_PS.cpp
+++ b/eeschema/plot_schematic_PS.cpp
@@ -34,6 +34,7 @@
 #include <reporter.h>
 #include <settings/settings_manager.h>
 #include <sch_painter.h>
+#include <schematic.h>
 #include <dialog_plot_schematic.h>
 #include <wx_html_report_panel.h>
 
@@ -52,7 +53,7 @@ void DIALOG_PLOT_SCHEMATIC::createPSFile( bool aPlotAll, bool aPlotFrameRef,
     SCH_SHEET_LIST  sheetList;
 
     if( aPlotAll )
-        sheetList.BuildSheetList( g_RootSheet );
+        sheetList.BuildSheetList( &m_parent->Schematic().Root() );
     else
         sheetList.push_back( m_parent->GetCurrentSheet() );
 
diff --git a/eeschema/plot_schematic_SVG.cpp b/eeschema/plot_schematic_SVG.cpp
index e6c10cda4a..89a5a3772f 100644
--- a/eeschema/plot_schematic_SVG.cpp
+++ b/eeschema/plot_schematic_SVG.cpp
@@ -34,6 +34,7 @@
 #include <base_units.h>
 #include <lib_edit_frame.h>
 #include <sch_sheet_path.h>
+#include <schematic.h>
 #include <project.h>
 #include <reporter.h>
 #include <settings/settings_manager.h>
@@ -51,7 +52,7 @@ void DIALOG_PLOT_SCHEMATIC::createSVGFile( bool aPrintAll, bool aPrintFrameRef,
     SCH_SHEET_LIST  sheetList;
 
     if( aPrintAll )
-        sheetList.BuildSheetList( g_RootSheet );
+        sheetList.BuildSheetList( &m_parent->Schematic().Root() );
     else
         sheetList.push_back( m_parent->GetCurrentSheet() );
 
diff --git a/eeschema/project_rescue.cpp b/eeschema/project_rescue.cpp
index 2c701e83f0..69820e9919 100644
--- a/eeschema/project_rescue.cpp
+++ b/eeschema/project_rescue.cpp
@@ -33,6 +33,7 @@
 #include <sch_component.h>
 #include <sch_sheet.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 #include <symbol_lib_table.h>
 #include <wildcards_and_files_ext.h>
 
@@ -59,9 +60,9 @@ static bool sort_by_libid( const SCH_COMPONENT* ref, SCH_COMPONENT* cmp )
  *
  * @param aComponents - a vector that will take the symbols
  */
-static void get_components( std::vector<SCH_COMPONENT*>& aComponents )
+static void get_components( SCHEMATIC* aSchematic, std::vector<SCH_COMPONENT*>& aComponents )
 {
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( aSchematic->Root() );
 
     // Get the full list
     for( SCH_SCREEN* screen = screens.GetFirst(); screen; screen = screens.GetNext() )
@@ -108,9 +109,9 @@ static LIB_PART* find_component( const wxString& aName, PART_LIBS* aLibs, bool a
 }
 
 
-static wxFileName GetRescueLibraryFileName()
+static wxFileName GetRescueLibraryFileName( SCHEMATIC* aSchematic )
 {
-    wxFileName fn( g_RootSheet->GetScreen()->GetFileName() );
+    wxFileName fn = aSchematic->GetFileName();
     fn.SetName( fn.GetName() + wxT( "-rescue" ) );
     fn.SetExt( SchematicLibraryFileExtension );
     return fn;
@@ -429,7 +430,7 @@ void RESCUE_SYMBOL_LIB_TABLE_CANDIDATE::FindRescues(
 
             // Differentiate symbol name in the rescue library by appending the symbol library
             // table nickname to the symbol name to prevent name clashes in the rescue library.
-            wxString libNickname = GetRescueLibraryFileName().GetName();
+            wxString libNickname = GetRescueLibraryFileName( aRescuer.Schematic() ).GetName();
 
             // Spaces in the file name will break the symbol name because they are not
             // quoted in the symbol library file format.
@@ -495,10 +496,14 @@ bool RESCUE_SYMBOL_LIB_TABLE_CANDIDATE::PerformAction( RESCUER* aRescuer )
 }
 
 
-RESCUER::RESCUER( PROJECT& aProject, SCH_SHEET_PATH* aCurrentSheet,
+RESCUER::RESCUER( PROJECT& aProject, SCHEMATIC* aSchematic, SCH_SHEET_PATH* aCurrentSheet,
                   EDA_DRAW_PANEL_GAL::GAL_TYPE aGalBackEndType )
 {
-    get_components( m_components );
+    m_schematic = aSchematic ? aSchematic : aCurrentSheet->LastScreen()->Schematic();
+
+    wxASSERT( m_schematic );
+
+    get_components( m_schematic, m_components );
     m_prj = &aProject;
     m_currentSheet = aCurrentSheet;
     m_galBackEndType = aGalBackEndType;
@@ -634,7 +639,7 @@ void LEGACY_RESCUER::InvokeDialog( wxWindow* aParent, bool aAskShowAgain )
 
 void LEGACY_RESCUER::OpenRescueLibrary()
 {
-    wxFileName fn = GetRescueLibraryFileName();
+    wxFileName fn = GetRescueLibraryFileName( m_schematic );
 
     std::unique_ptr<PART_LIB> rescue_lib( new PART_LIB( LIBRARY_TYPE_EESCHEMA, fn.GetFullPath() ) );
 
@@ -736,10 +741,8 @@ bool LEGACY_RESCUER::WriteRescueLibrary( wxWindow *aParent )
     m_prj->SetElem( PROJECT::ELEM_SCH_PART_LIBS, libs );
 
     // Update the schematic symbol library links since the library list has changed.
-    SCH_SCREENS schematic;
-
+    SCH_SCREENS schematic( m_schematic->Root() );
     schematic.UpdateSymbolLinks();
-
     return true;
 }
 
@@ -753,10 +756,10 @@ void LEGACY_RESCUER::AddPart( LIB_PART* aNewPart )
 }
 
 
-SYMBOL_LIB_TABLE_RESCUER::SYMBOL_LIB_TABLE_RESCUER( PROJECT& aProject,
+SYMBOL_LIB_TABLE_RESCUER::SYMBOL_LIB_TABLE_RESCUER( PROJECT& aProject, SCHEMATIC* aSchematic,
                                                     SCH_SHEET_PATH* aCurrentSheet,
                                                     EDA_DRAW_PANEL_GAL::GAL_TYPE aGalBackEndType ) :
-    RESCUER( aProject, aCurrentSheet, aGalBackEndType )
+    RESCUER( aProject, aSchematic, aCurrentSheet, aGalBackEndType )
 {
     m_properties = std::make_unique<PROPERTIES>();
 }
@@ -785,7 +788,7 @@ void SYMBOL_LIB_TABLE_RESCUER::OpenRescueLibrary()
 bool SYMBOL_LIB_TABLE_RESCUER::WriteRescueLibrary( wxWindow *aParent )
 {
     wxString msg;
-    wxFileName fn = GetRescueLibraryFileName();
+    wxFileName fn = GetRescueLibraryFileName( m_schematic );
 
     // If the rescue library already exists in the symbol library table no need save it to add
     // it to the table.
@@ -835,8 +838,7 @@ bool SYMBOL_LIB_TABLE_RESCUER::WriteRescueLibrary( wxWindow *aParent )
         return false;
 
     // Update the schematic symbol library links since the library list has changed.
-    SCH_SCREENS schematic;
-
+    SCH_SCREENS schematic( m_schematic->Root() );
     schematic.UpdateSymbolLinks();
     return true;
 }
@@ -846,7 +848,7 @@ void SYMBOL_LIB_TABLE_RESCUER::AddPart( LIB_PART* aNewPart )
 {
     wxCHECK_RET( aNewPart, "Invalid LIB_PART pointer." );
 
-    wxFileName fn = GetRescueLibraryFileName();
+    wxFileName fn = GetRescueLibraryFileName( m_schematic );
 
     try
     {
diff --git a/eeschema/project_rescue.h b/eeschema/project_rescue.h
index 250cda2bc4..1fa3d6a20b 100644
--- a/eeschema/project_rescue.h
+++ b/eeschema/project_rescue.h
@@ -53,6 +53,7 @@ class RESCUER;
 class SCH_EDIT_FRAME;
 class SCH_LEGACY_PLUGIN;
 class SCH_SHEET_PATH;
+class SCHEMATIC;
 
 
 enum RESCUE_TYPE
@@ -234,6 +235,7 @@ protected:
 
     std::vector<SCH_COMPONENT*> m_components;
     PROJECT* m_prj;
+    SCHEMATIC* m_schematic;
     EDA_DRAW_PANEL_GAL::GAL_TYPE m_galBackEndType;
     SCH_SHEET_PATH* m_currentSheet;
 
@@ -243,7 +245,7 @@ protected:
     std::vector<RESCUE_LOG> m_rescue_log;
 
 public:
-    RESCUER( PROJECT& aProject, SCH_SHEET_PATH* aCurrentSheet,
+    RESCUER( PROJECT& aProject, SCHEMATIC* aSchematic, SCH_SHEET_PATH* aCurrentSheet,
              EDA_DRAW_PANEL_GAL::GAL_TYPE aGalBackeEndType );
 
     virtual ~RESCUER()
@@ -299,6 +301,8 @@ public:
      */
     PROJECT* GetPrj() { return m_prj; }
 
+    SCHEMATIC* Schematic() { return m_schematic; }
+
     /**
      * Used by individual #RESCUE_CANDIDATE objects to log a rescue for undoing.
      */
@@ -327,9 +331,9 @@ private:
     std::unique_ptr<PART_LIB> m_rescue_lib;
 
 public:
-    LEGACY_RESCUER( PROJECT& aProject, SCH_SHEET_PATH* aCurrentSheet,
+    LEGACY_RESCUER( PROJECT& aProject, SCHEMATIC* aSchematic, SCH_SHEET_PATH* aCurrentSheet,
                     EDA_DRAW_PANEL_GAL::GAL_TYPE aGalBackEndType ) :
-        RESCUER( aProject, aCurrentSheet, aGalBackEndType )
+        RESCUER( aProject, aSchematic, aCurrentSheet, aGalBackEndType )
     {
     }
 
@@ -357,7 +361,8 @@ private:
     std::unique_ptr< PROPERTIES > m_properties;   ///< Library plugin properties
 
 public:
-    SYMBOL_LIB_TABLE_RESCUER( PROJECT& aProject, SCH_SHEET_PATH* aCurrentSheet,
+    SYMBOL_LIB_TABLE_RESCUER( PROJECT& aProject, SCHEMATIC* aSchematic,
+                              SCH_SHEET_PATH* aCurrentSheet,
                               EDA_DRAW_PANEL_GAL::GAL_TYPE aGalBackeEndType );
 
     virtual ~SYMBOL_LIB_TABLE_RESCUER()
diff --git a/eeschema/sch_base_frame.cpp b/eeschema/sch_base_frame.cpp
index 751941973e..f334322050 100644
--- a/eeschema/sch_base_frame.cpp
+++ b/eeschema/sch_base_frame.cpp
@@ -345,35 +345,6 @@ void SCH_BASE_FRAME::CenterScreen( const wxPoint& aCenterPoint, bool aWarpPointe
 }
 
 
-void SCH_BASE_FRAME::FocusOnItem( SCH_ITEM* aItem )
-{
-    static KIID lastBrightenedItemID( niluuid );
-
-    SCH_SHEET_LIST sheetList( g_RootSheet );
-    SCH_SHEET_PATH dummy;
-    SCH_ITEM*      lastItem = sheetList.GetItem( lastBrightenedItemID, &dummy );
-
-    if( lastItem && lastItem != aItem )
-    {
-        lastItem->ClearBrightened();
-
-        RefreshItem( lastItem );
-        lastBrightenedItemID = niluuid;
-    }
-
-    if( aItem )
-    {
-        aItem->SetBrightened();
-
-        RefreshItem( aItem );
-        lastBrightenedItemID = aItem->m_Uuid;
-
-        // JEY TODO: test this with pins and fields (and with rotated symbols) ....
-        FocusOnLocation( aItem->GetFocusPosition() );
-    }
-}
-
-
 void SCH_BASE_FRAME::HardRedraw()
 {
     GetCanvas()->GetView()->UpdateAllItems( KIGFX::ALL );
diff --git a/eeschema/sch_bus_entry.cpp b/eeschema/sch_bus_entry.cpp
index 96f42f660c..4d6731734d 100644
--- a/eeschema/sch_bus_entry.cpp
+++ b/eeschema/sch_bus_entry.cpp
@@ -34,6 +34,7 @@
 #include <eeschema_config.h>
 #include <general.h>
 #include <sch_bus_entry.h>
+#include <sch_edit_frame.h>
 #include <sch_line.h>
 #include <sch_text.h>
 #include <settings/color_settings.h>
@@ -402,7 +403,13 @@ void SCH_BUS_ENTRY_BASE::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, MSG_PANEL_ITEM
     }
 
     aList.push_back( MSG_PANEL_ITEM( _( "Bus Entry Type" ), msg, DARKCYAN ) );
-    if( auto conn = Connection( *g_CurrentSheet ) )
+
+    SCH_EDIT_FRAME* frame = dynamic_cast<SCH_EDIT_FRAME*>( aFrame );
+
+    if( !frame )
+        return;
+
+    if( auto conn = Connection( frame->GetCurrentSheet() ) )
     {
 #if defined(DEBUG)
         conn->AppendDebugInfoToMsgPanel( aList );
diff --git a/eeschema/sch_component.cpp b/eeschema/sch_component.cpp
index 61ff7de27b..aae2bb8ed3 100644
--- a/eeschema/sch_component.cpp
+++ b/eeschema/sch_component.cpp
@@ -37,6 +37,7 @@
 #include <sch_component.h>
 #include <sch_sheet.h>
 #include <sch_sheet_path.h>
+#include <schematic.h>
 #include <netlist_object.h>
 #include <lib_item.h>
 
@@ -722,13 +723,17 @@ void SCH_COMPONENT::GetPins( std::vector<LIB_PIN*>& aPinsList )
 
 SCH_PIN_PTRS SCH_COMPONENT::GetSchPins( const SCH_SHEET_PATH* aSheet ) const
 {
-    if( aSheet == nullptr )
-        aSheet = g_CurrentSheet;
-
-    // TODO(JE) if this works, consider caching in m_sheet_pins
-    int unit = GetUnitSelection( aSheet );
     SCH_PIN_PTRS ptrs;
 
+    if( aSheet == nullptr )
+    {
+        wxCHECK_MSG( Schematic(), ptrs, "Can't call GetSchPins on a component with no schematic" );
+
+        aSheet = &Schematic()->CurrentSheet();
+    }
+
+    int unit = GetUnitSelection( aSheet );
+
     for( const auto& p : m_pins )
     {
         if( unit && p->GetLibPin()->GetUnit() && ( p->GetLibPin()->GetUnit() != unit ) )
@@ -1160,14 +1165,18 @@ void SCH_COMPONENT::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, MSG_PANEL_ITEMS& aL
 {
     wxString msg;
 
+    SCH_EDIT_FRAME* schframe = dynamic_cast<SCH_EDIT_FRAME*>( aFrame );
+
     // part and alias can differ if alias is not the root
     if( m_part )
     {
         if( m_part.get() != dummy() )
         {
-            if( g_CurrentSheet )
-                aList.push_back( MSG_PANEL_ITEM( _( "Reference" ), GetRef( g_CurrentSheet ),
-                                                 DARKCYAN ) );
+            if( schframe )
+            {
+                aList.push_back( MSG_PANEL_ITEM(
+                        _( "Reference" ), GetRef( &schframe->GetCurrentSheet() ), DARKCYAN ) );
+            }
 
             msg = m_part->IsPower() ? _( "Power symbol" ) : _( "Value" );
 
@@ -1213,9 +1222,11 @@ void SCH_COMPONENT::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, MSG_PANEL_ITEMS& aL
     }
     else
     {
-        if( g_CurrentSheet )
-            aList.push_back( MSG_PANEL_ITEM( _( "Reference" ), GetRef( g_CurrentSheet ),
-                                             DARKCYAN ) );
+        if( schframe )
+        {
+            aList.push_back( MSG_PANEL_ITEM(
+                    _( "Reference" ), GetRef( &schframe->GetCurrentSheet() ), DARKCYAN ) );
+        }
 
         aList.push_back( MSG_PANEL_ITEM( _( "Value" ), GetField( VALUE )->GetShownText(),
                                          DARKCYAN ) );
diff --git a/eeschema/sch_connection.cpp b/eeschema/sch_connection.cpp
index d98e824b37..d6a8c1d765 100644
--- a/eeschema/sch_connection.cpp
+++ b/eeschema/sch_connection.cpp
@@ -150,7 +150,7 @@ void SCH_CONNECTION::ConfigureFromLabel( const wxString& aLabel )
         for( const wxString& group_member : members )
         {
             // Handle alias inside bus group member list
-            if( auto alias = g_ConnectionGraph->GetBusAlias( group_member ) )
+            if( auto alias = m_graph->GetBusAlias( group_member ) )
             {
                 for( const wxString& alias_member : alias->Members() )
                 {
@@ -332,7 +332,7 @@ void SCH_CONNECTION::AppendInfoToMsgPanel( MSG_PANEL_ITEMS& aList ) const
     }
 #endif
 
-    if( auto alias = g_ConnectionGraph->GetBusAlias( m_name ) )
+    if( auto alias = m_graph->GetBusAlias( m_name ) )
     {
         msg.Printf( _( "Bus Alias %s Members" ), m_name );
 
@@ -347,7 +347,7 @@ void SCH_CONNECTION::AppendInfoToMsgPanel( MSG_PANEL_ITEMS& aList ) const
     {
         for( const auto& group_member : group_members )
         {
-            if( auto group_alias = g_ConnectionGraph->GetBusAlias( group_member ) )
+            if( auto group_alias = m_graph->GetBusAlias( group_member ) )
             {
                 msg.Printf( _( "Bus Alias %s Members" ), group_alias->GetName() );
 
diff --git a/eeschema/sch_connection.h b/eeschema/sch_connection.h
index c929eb8b13..c9ed9a2993 100644
--- a/eeschema/sch_connection.h
+++ b/eeschema/sch_connection.h
@@ -32,6 +32,7 @@
 #include <sch_sheet_path.h>
 
 
+class CONNECTION_GRAPH;
 class SCH_ITEM;
 class SCH_SHEET_PATH;
 
@@ -73,6 +74,11 @@ public:
 
     bool operator!=( const SCH_CONNECTION& aOther ) const;
 
+    void SetGraph( CONNECTION_GRAPH* aGraph )
+    {
+        m_graph = aGraph;
+    }
+
     /**
      * Configures the connection given a label.
      * For CONNECTION_NET, this just sets the name.
@@ -370,6 +376,12 @@ private:
      */
     std::vector< std::shared_ptr< SCH_CONNECTION > > m_members;
 
+    /**
+     * Pointer to the connection graph for the schematic this connection exists on.
+     * Needed for bus alias lookups.
+     */
+    CONNECTION_GRAPH* m_graph;
+
 };
 
 #endif
diff --git a/eeschema/sch_eagle_plugin.cpp b/eeschema/sch_eagle_plugin.cpp
index 2c55255177..43e8abb5dd 100644
--- a/eeschema/sch_eagle_plugin.cpp
+++ b/eeschema/sch_eagle_plugin.cpp
@@ -57,6 +57,7 @@
 #include <sch_sheet.h>
 #include <sch_sheet_path.h>
 #include <sch_text.h>
+#include <schematic.h>
 #include <symbol_lib_table.h>
 #include <template_fieldnames.h>
 #include <wildcards_and_files_ext.h>
@@ -389,7 +390,8 @@ int SCH_EAGLE_PLUGIN::GetModifyHash() const
 }
 
 
-SCH_SHEET* SCH_EAGLE_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCH_SHEET* aAppendToMe,
+SCH_SHEET* SCH_EAGLE_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCHEMATIC* aSchematic,
+        SCH_SHEET* aAppendToMe,
         const PROPERTIES* aProperties )
 {
     wxASSERT( !aFileName || aKiway != NULL );
@@ -398,8 +400,9 @@ SCH_SHEET* SCH_EAGLE_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCH
     // Load the document
     wxXmlDocument xmlDocument;
 
-    m_filename = aFileName;
-    m_kiway    = aKiway;
+    m_filename  = aFileName;
+    m_kiway     = aKiway;
+    m_schematic = aSchematic;
 
     if( !xmlDocument.Load( m_filename.GetFullPath() ) )
         THROW_IO_ERROR(
@@ -410,11 +413,12 @@ SCH_SHEET* SCH_EAGLE_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCH
 
     if( aAppendToMe )
     {
-        m_rootSheet = aAppendToMe->GetRootSheet();
+        wxCHECK_MSG( aSchematic->IsValid(), nullptr, "Can't append to a schematic with no root!" );
+        m_rootSheet = &aSchematic->Root();
     }
     else
     {
-        m_rootSheet = new SCH_SHEET();
+        m_rootSheet = new SCH_SHEET( aSchematic );
         m_rootSheet->SetFileName( aFileName );
     }
 
@@ -422,6 +426,7 @@ SCH_SHEET* SCH_EAGLE_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCH
     {
         SCH_SCREEN* screen = new SCH_SCREEN( aKiway );
         screen->SetFileName( aFileName );
+        screen->SetParent( m_schematic );
         m_rootSheet->SetScreen( screen );
     }
 
@@ -593,12 +598,12 @@ void SCH_EAGLE_PLUGIN::loadSchematic( wxXmlNode* aSchematicNode )
         while( sheetNode )
         {
             wxPoint                    pos = wxPoint( x * Mils2iu( 1000 ), y * Mils2iu( 1000 ) );
-            std::unique_ptr<SCH_SHEET> sheet( new SCH_SHEET( pos ) );
+            std::unique_ptr<SCH_SHEET> sheet( new SCH_SHEET( m_rootSheet, pos ) );
             SCH_SCREEN*                screen = new SCH_SCREEN( m_kiway );
 
-            sheet->SetParent( m_rootSheet );
             sheet->SetScreen( screen );
             sheet->GetScreen()->SetFileName( sheet->GetFileName() );
+            sheet->GetScreen()->SetParent( m_schematic );
 
             m_currentSheet = sheet.get();
             loadSheet( sheetNode, i );
diff --git a/eeschema/sch_eagle_plugin.h b/eeschema/sch_eagle_plugin.h
index caa5547601..9e02351596 100644
--- a/eeschema/sch_eagle_plugin.h
+++ b/eeschema/sch_eagle_plugin.h
@@ -91,8 +91,8 @@ public:
 
     int GetModifyHash() const override;
 
-    SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway, SCH_SHEET* aAppendToMe = NULL,
-                     const PROPERTIES* aProperties = NULL ) override;
+    SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway, SCHEMATIC* aSchematic,
+                     SCH_SHEET* aAppendToMe = NULL, const PROPERTIES* aProperties = NULL ) override;
 
     bool CheckHeader( const wxString& aFileName ) override;
 
@@ -188,6 +188,7 @@ private:
     wxString m_version; ///< Eagle file version.
     wxFileName m_filename;
     wxString m_libName; ///< Library name to save symbols
+    SCHEMATIC* m_schematic;   ///< Passed to Load(), the schematic object being loaded
 
     EPART_MAP m_partlist;
     std::map<wxString, EAGLE_LIBRARY> m_eagleLibs;
diff --git a/eeschema/sch_edit_frame.cpp b/eeschema/sch_edit_frame.cpp
index 65959dc868..0effab9165 100644
--- a/eeschema/sch_edit_frame.cpp
+++ b/eeschema/sch_edit_frame.cpp
@@ -49,6 +49,7 @@
 #include <sch_edit_frame.h>
 #include <sch_painter.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 #include <advanced_config.h>
 #include <sim/sim_plot_frame.h>
 #include <symbol_lib_table.h>
@@ -73,10 +74,6 @@
 
 #include <gal/graphics_abstraction_layer.h>
 
-SCH_SHEET_PATH* g_CurrentSheet = nullptr; // declared in general.h
-CONNECTION_GRAPH* g_ConnectionGraph = nullptr;
-ERC_SETTINGS* g_ErcSettings = nullptr;
-
 // non-member so it can be moved easily, and kept REALLY private.
 // Do NOT Clear() in here.
 static void add_search_paths( SEARCH_STACK* aDst, const SEARCH_STACK& aSrc, int aIndex )
@@ -210,9 +207,7 @@ SCH_EDIT_FRAME::SCH_EDIT_FRAME( KIWAY* aKiway, wxWindow* aParent ):
         wxDefaultPosition, wxDefaultSize, KICAD_DEFAULT_DRAWFRAME_STYLE, SCH_EDIT_FRAME_NAME ),
     m_item_to_repeat( nullptr )
 {
-    g_CurrentSheet = new SCH_SHEET_PATH();
-    g_ConnectionGraph = new CONNECTION_GRAPH( this );
-    g_ErcSettings = new ERC_SETTINGS();
+    m_schematic = new SCHEMATIC();
 
     m_showBorderAndTitleBlock = true;   // true to show sheet references
     m_hasAutoSave = true;
@@ -269,6 +264,9 @@ SCH_EDIT_FRAME::SCH_EDIT_FRAME( KIWAY* aKiway, wxWindow* aParent ):
     {
         GetCanvas()->GetGAL()->SetGridVisibility( IsGridVisible() );
         GetCanvas()->GetGAL()->SetAxesEnabled( false );
+
+        if( auto p = dynamic_cast<KIGFX::SCH_PAINTER*>( GetCanvas()->GetView()->GetPainter() ) )
+            p->SetSchematic( m_schematic );
     }
 
     InitExitKey();
@@ -296,15 +294,7 @@ SCH_EDIT_FRAME::~SCH_EDIT_FRAME()
 
     SetScreen( NULL );
 
-    delete g_CurrentSheet;          // a SCH_SHEET_PATH, on the heap.
-    delete g_ConnectionGraph;
-    delete g_RootSheet;
-    delete g_ErcSettings;
-
-    g_CurrentSheet = nullptr;
-    g_ConnectionGraph = nullptr;
-    g_RootSheet = nullptr;
-    g_ErcSettings = nullptr;
+    delete m_schematic;
 }
 
 
@@ -358,58 +348,54 @@ void SCH_EDIT_FRAME::SaveCopyForRepeatItem( SCH_ITEM* aItem )
 
 EDA_ITEM* SCH_EDIT_FRAME::GetItem( const KIID& aId )
 {
-    SCH_SHEET_LIST schematic( g_RootSheet );
-    SCH_SHEET_PATH dummy;
-
-    return schematic.GetItem( aId, &dummy );
+    return Schematic().GetSheets().GetItem( aId );
 }
 
 
 void SCH_EDIT_FRAME::SetSheetNumberAndCount()
 {
     SCH_SCREEN* screen;
-    SCH_SCREENS s_list;
+    SCH_SCREENS s_list( Schematic().Root() );
 
     // Set the sheet count, and the sheet number (1 for root sheet)
-    int              sheet_count = g_RootSheet->CountSheets();
-    int              SheetNumber = 1;
-    const KIID_PATH& current_sheetpath = g_CurrentSheet->Path();
-    SCH_SHEET_LIST   sheetList( g_RootSheet );
+    int              sheet_count       = Schematic().Root().CountSheets();
+    int              sheet_number      = 1;
+    const KIID_PATH& current_sheetpath = GetCurrentSheet().Path();
 
     // Examine all sheets path to find the current sheets path,
     // and count them from root to the current sheet path:
-    for( const SCH_SHEET_PATH& sheet : sheetList )
+    for( const SCH_SHEET_PATH& sheet : Schematic().GetSheets() )
     {
         if( sheet.Path() == current_sheetpath )   // Current sheet path found
             break;
 
-        SheetNumber++;                         // Not found, increment before this current path
+        sheet_number++;                         // Not found, increment before this current path
     }
 
-    g_CurrentSheet->SetPageNumber( SheetNumber );
+    GetCurrentSheet().SetPageNumber( sheet_number );
 
     for( screen = s_list.GetFirst(); screen != NULL; screen = s_list.GetNext() )
         screen->m_NumberOfScreens = sheet_count;
 
-    GetScreen()->m_ScreenNumber = SheetNumber;
+    GetScreen()->m_ScreenNumber = sheet_number;
 }
 
 
 SCH_SCREEN* SCH_EDIT_FRAME::GetScreen() const
 {
-    if( !g_CurrentSheet )
-        return nullptr;
+    return GetCurrentSheet().LastScreen();
+}
 
-    return g_CurrentSheet->LastScreen();
+
+SCHEMATIC& SCH_EDIT_FRAME::Schematic() const
+{
+    return *m_schematic;
 }
 
 
 wxString SCH_EDIT_FRAME::GetScreenDesc() const
 {
-    if(! g_CurrentSheet )
-        return wxT("<unknown>");
-
-    wxString s = g_CurrentSheet->PathHumanReadable();
+    wxString s = GetCurrentSheet().PathHumanReadable();
 
     return s;
 }
@@ -417,22 +403,17 @@ wxString SCH_EDIT_FRAME::GetScreenDesc() const
 
 void SCH_EDIT_FRAME::CreateScreens()
 {
-    if( g_RootSheet == NULL )
-        g_RootSheet = new SCH_SHEET();
+    m_schematic->Reset();
+    m_schematic->SetRoot( new SCH_SHEET( m_schematic ) );
 
-    if( g_RootSheet->GetScreen() == NULL )
-    {
-        SCH_SCREEN* screen = new SCH_SCREEN( &Kiway() );
-        screen->SetMaxUndoItems( m_UndoRedoCountMax );
-        g_RootSheet->SetScreen( screen );
-        SetScreen( g_RootSheet->GetScreen() );
-    }
+    SCH_SCREEN* rootScreen = new SCH_SCREEN( &Kiway() );
+    rootScreen->SetMaxUndoItems( m_UndoRedoCountMax );
+    m_schematic->Root().SetScreen( rootScreen );
+    SetScreen( Schematic().RootScreen() );
 
-    g_RootSheet->GetScreen()->SetFileName( wxEmptyString );
+    m_schematic->RootScreen()->SetFileName( wxEmptyString );
 
-    g_CurrentSheet->clear();
-    g_CurrentSheet->push_back( g_RootSheet );
-    g_ConnectionGraph->Reset();
+    GetCurrentSheet().push_back( &m_schematic->Root() );
 
     if( GetScreen() == NULL )
     {
@@ -445,22 +426,20 @@ void SCH_EDIT_FRAME::CreateScreens()
 }
 
 
-SCH_SHEET_PATH& SCH_EDIT_FRAME::GetCurrentSheet()
+SCH_SHEET_PATH& SCH_EDIT_FRAME::GetCurrentSheet() const
 {
-    wxASSERT_MSG( g_CurrentSheet != NULL, wxT( "SCH_EDIT_FRAME g_CurrentSheet member is NULL." ) );
-
-    return *g_CurrentSheet;
+    return m_schematic->CurrentSheet();
 }
 
 
 void SCH_EDIT_FRAME::SetCurrentSheet( const SCH_SHEET_PATH& aSheet )
 {
-    if( aSheet != *g_CurrentSheet )
+    if( aSheet != GetCurrentSheet() )
     {
         FocusOnItem( nullptr );
 
-        *g_CurrentSheet = aSheet;
-        GetCanvas()->DisplaySheet( g_CurrentSheet->LastScreen() );
+        Schematic().SetCurrentSheet( aSheet );
+        GetCanvas()->DisplaySheet( aSheet.LastScreen() );
     }
 }
 
@@ -469,18 +448,16 @@ void SCH_EDIT_FRAME::HardRedraw()
 {
     FocusOnItem( nullptr );
 
-    GetCanvas()->DisplaySheet( g_CurrentSheet->LastScreen() );
+    GetCanvas()->DisplaySheet( GetCurrentSheet().LastScreen() );
     GetCanvas()->ForceRefresh();
 }
 
 
 void SCH_EDIT_FRAME::OnCloseWindow( wxCloseEvent& aEvent )
 {
-    SCH_SHEET_LIST sheetList( g_RootSheet );
-
     // Shutdown blocks must be determined and vetoed as early as possible
     if( SupportsShutdownBlockReason() && aEvent.GetId() == wxEVT_QUERY_END_SESSION
-            && sheetList.IsModified() )
+            && Schematic().GetSheets().IsModified() )
     {
         aEvent.Veto();
         return;
@@ -507,9 +484,11 @@ void SCH_EDIT_FRAME::OnCloseWindow( wxCloseEvent& aEvent )
     if( simFrame && !simFrame->Close() )   // Can close the simulator?
         return;
 
-    if( sheetList.IsModified() )
+    SCH_SHEET_LIST sheetlist = Schematic().GetSheets();
+
+    if( sheetlist.IsModified() )
     {
-        wxFileName fileName = g_RootSheet->GetScreen()->GetFileName();
+        wxFileName fileName = Schematic().RootScreen()->GetFileName();
         wxString msg = _( "Save changes to \"%s\" before closing?" );
 
         if( !HandleUnsavedChanges( this, wxString::Format( msg, fileName.GetFullName() ),
@@ -546,7 +525,7 @@ void SCH_EDIT_FRAME::OnCloseWindow( wxCloseEvent& aEvent )
     if( FindHierarchyNavigator() )
         FindHierarchyNavigator()->Close( true );
 
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( Schematic().Root() );
     wxFileName fn;
 
     for( SCH_SCREEN* screen = screens.GetFirst(); screen != NULL; screen = screens.GetNext() )
@@ -560,17 +539,17 @@ void SCH_EDIT_FRAME::OnCloseWindow( wxCloseEvent& aEvent )
             wxRemoveFile( fn.GetFullPath() );
     }
 
-    sheetList.ClearModifyStatus();
+    sheetlist.ClearModifyStatus();
 
-    wxString fileName = Prj().AbsolutePath( g_RootSheet->GetScreen()->GetFileName() );
+    wxString fileName = Prj().AbsolutePath( Schematic().RootScreen()->GetFileName() );
 
-    if( !g_RootSheet->GetScreen()->GetFileName().IsEmpty() && !g_RootSheet->GetScreen()->IsEmpty() )
+    if( !Schematic().GetFileName().IsEmpty() && !Schematic().RootScreen()->IsEmpty() )
         UpdateFileHistory( fileName );
 
-    g_RootSheet->GetScreen()->Clear();
+    Schematic().RootScreen()->Clear();
 
     // all sub sheets are deleted, only the main sheet is usable
-    g_CurrentSheet->clear();
+    GetCurrentSheet().clear();
 
     Destroy();
 }
@@ -582,11 +561,11 @@ wxString SCH_EDIT_FRAME::GetUniqueFilenameForCurrentSheet()
     // Note that we need to fetch the rootSheetName out of its filename, as the root SCH_SHEET's
     // name is just a timestamp.
 
-    wxFileName rootFn( g_CurrentSheet->at( 0 )->GetFileName() );
+    wxFileName rootFn( GetCurrentSheet().at( 0 )->GetFileName() );
     wxString   filename = rootFn.GetName();
 
-    for( unsigned i = 1; i < g_CurrentSheet->size(); i++ )
-        filename += wxT( "-" ) + g_CurrentSheet->at( i )->GetName();
+    for( unsigned i = 1; i < GetCurrentSheet().size(); i++ )
+        filename += wxT( "-" ) + GetCurrentSheet().at( i )->GetName();
 
     return filename;
 }
@@ -611,7 +590,7 @@ void SCH_EDIT_FRAME::OnModify()
 
 void SCH_EDIT_FRAME::OnUpdatePCB( wxCommandEvent& event )
 {
-    wxFileName fn = Prj().AbsolutePath( g_RootSheet->GetScreen()->GetFileName() );
+    wxFileName fn = Prj().AbsolutePath( Schematic().GetFileName() );
 
     fn.SetExt( PcbFileExtension );
 
@@ -811,7 +790,7 @@ void SCH_EDIT_FRAME::ParseArgs( wxCmdLineParser& aParser )
 
 void SCH_EDIT_FRAME::OnOpenPcbnew( wxCommandEvent& event )
 {
-    wxFileName kicad_board = Prj().AbsolutePath( g_RootSheet->GetScreen()->GetFileName() );
+    wxFileName kicad_board = Prj().AbsolutePath( Schematic().GetFileName() );
 
     if( kicad_board.IsOk() )
     {
@@ -857,7 +836,7 @@ void SCH_EDIT_FRAME::OnOpenPcbnew( wxCommandEvent& event )
 
 void SCH_EDIT_FRAME::OnOpenCvpcb( wxCommandEvent& event )
 {
-    wxFileName fn = Prj().AbsolutePath( g_RootSheet->GetScreen()->GetFileName() );
+    wxFileName fn = Prj().AbsolutePath( Schematic().GetFileName() );
     fn.SetExt( NetlistFileExtension );
 
     if( !prepareForNetlist() )
@@ -909,9 +888,9 @@ bool SCH_EDIT_FRAME::isAutoSaveRequired() const
     // In case this event happens before g_RootSheet is initialized which does happen
     // on mingw64 builds.
 
-    if( g_RootSheet != NULL )
+    if( Schematic().IsValid() )
     {
-        SCH_SCREENS screenList;
+        SCH_SCREENS screenList( Schematic().Root() );
 
         for( SCH_SCREEN* screen = screenList.GetFirst(); screen; screen = screenList.GetNext() )
         {
@@ -1004,7 +983,7 @@ void SCH_EDIT_FRAME::AddItemToScreenAndUndoList( SCH_ITEM* aItem, bool aUndoAppe
 
         TestDanglingEnds();
 
-        for( SCH_ITEM* item : aItem->ConnectedItems( *g_CurrentSheet ) )
+        for( SCH_ITEM* item : aItem->ConnectedItems( GetCurrentSheet() ) )
             RefreshItem( item );
     }
 
@@ -1028,7 +1007,7 @@ void SCH_EDIT_FRAME::UpdateTitle()
 
         title.Printf( _( "Eeschema" ) + wxT( " \u2014 %s [%s] \u2014 %s" ),
                       fn.GetFullName(),
-                      g_CurrentSheet->PathHumanReadable(),
+                      GetCurrentSheet().PathHumanReadable(),
                       fn.GetPath() );
 
         if( fn.FileExists() )
@@ -1044,15 +1023,9 @@ void SCH_EDIT_FRAME::UpdateTitle()
 }
 
 
-int SCH_EDIT_FRAME::GetSeverity( int aErrorCode ) const
-{
-    return ::GetSeverity( aErrorCode );
-}
-
-
 void SCH_EDIT_FRAME::RecalculateConnections( SCH_CLEANUP_FLAGS aCleanupFlags )
 {
-    SCH_SHEET_LIST list( g_RootSheet );
+    SCH_SHEET_LIST list = Schematic().GetSheets();
     PROF_COUNTER   timer;
 
     // Ensure schematic graph is accurate
@@ -1069,7 +1042,7 @@ void SCH_EDIT_FRAME::RecalculateConnections( SCH_CLEANUP_FLAGS aCleanupFlags )
     timer.Stop();
     wxLogTrace( "CONN_PROFILE", "SchematicCleanUp() %0.4f ms", timer.msecs() );
 
-    g_ConnectionGraph->Recalculate( list, true );
+    Schematic().ConnectionGraph()->Recalculate( list, true );
 }
 
 
@@ -1133,8 +1106,7 @@ void SCH_EDIT_FRAME::FixupJunctions()
 
     bool modified = false;
 
-    SCH_SHEET_LIST sheetList;
-    sheetList.BuildSheetList( g_RootSheet );
+    SCH_SHEET_LIST sheetList = Schematic().GetSheets();
 
     for( const SCH_SHEET_PATH& sheet : sheetList )
     {
@@ -1179,9 +1151,7 @@ void SCH_EDIT_FRAME::FixupJunctions()
 
 bool SCH_EDIT_FRAME::IsContentModified()
 {
-    SCH_SHEET_LIST sheetList( g_RootSheet );
-
-    return sheetList.IsModified();
+    return Schematic().GetSheets().IsModified();
 }
 
 
@@ -1192,6 +1162,35 @@ bool SCH_EDIT_FRAME::GetShowAllPins() const
 }
 
 
+void SCH_EDIT_FRAME::FocusOnItem( SCH_ITEM* aItem )
+{
+    static KIID lastBrightenedItemID( niluuid );
+
+    SCH_SHEET_LIST sheetList = Schematic().GetSheets();
+    SCH_SHEET_PATH dummy;
+    SCH_ITEM*      lastItem = sheetList.GetItem( lastBrightenedItemID, &dummy );
+
+    if( lastItem && lastItem != aItem )
+    {
+        lastItem->ClearBrightened();
+
+        RefreshItem( lastItem );
+        lastBrightenedItemID = niluuid;
+    }
+
+    if( aItem )
+    {
+        aItem->SetBrightened();
+
+        RefreshItem( aItem );
+        lastBrightenedItemID = aItem->m_Uuid;
+
+        // JEY TODO: test this with pins and fields (and with rotated symbols) ....
+        FocusOnLocation( aItem->GetFocusPosition() );
+    }
+}
+
+
 void SCH_EDIT_FRAME::ConvertTimeStampUuids()
 {
     // Remove this once this method is fully implemented.  Otherwise, don't use it.
@@ -1201,14 +1200,14 @@ void SCH_EDIT_FRAME::ConvertTimeStampUuids()
     // sheet paths using the new UUID based sheet paths.
 
     // Save the time stamp sheet paths.
-    SCH_SHEET_LIST timeStampSheetPaths( g_RootSheet );
+    SCH_SHEET_LIST timeStampSheetPaths = Schematic().GetSheets();
 
     std::vector<KIID_PATH> oldSheetPaths = timeStampSheetPaths.GetPaths();
 
     // The root sheet now gets a permanent UUID.
-    const_cast<KIID&>( g_RootSheet->m_Uuid ).ConvertTimestampToUuid();
+    const_cast<KIID&>( Schematic().Root().m_Uuid ).ConvertTimestampToUuid();
 
-    SCH_SCREENS schematic;
+    SCH_SCREENS schematic( Schematic().Root() );
 
     // Change the sheet and symbol time stamps to UUIDs.
     for( SCH_SCREEN* screen = schematic.GetFirst(); screen; screen = schematic.GetNext() )
@@ -1220,18 +1219,11 @@ void SCH_EDIT_FRAME::ConvertTimeStampUuids()
             const_cast<KIID&>( symbol->m_Uuid ).ConvertTimestampToUuid();
     }
 
-    SCH_SHEET_LIST uuidSheetPaths( g_RootSheet );
-
     timeStampSheetPaths.ReplaceLegacySheetPaths( oldSheetPaths );
 }
 
 
 wxString SCH_EDIT_FRAME::GetCurrentFileName() const
 {
-    SCH_SCREEN* screen = g_RootSheet->GetScreen();
-
-    if( screen )
-        return screen->GetFileName();
-
-    return wxEmptyString;
+    return Schematic().GetFileName();
 }
diff --git a/eeschema/sch_edit_frame.h b/eeschema/sch_edit_frame.h
index 441943d8ac..87d37a576c 100644
--- a/eeschema/sch_edit_frame.h
+++ b/eeschema/sch_edit_frame.h
@@ -58,6 +58,7 @@ class SCH_SHEET_PIN;
 class SCH_COMPONENT;
 class SCH_FIELD;
 class SCH_JUNCTION;
+class SCHEMATIC;
 class DIALOG_SCH_FIND;
 class wxFindReplaceData;
 class RESCUER;
@@ -121,6 +122,7 @@ class SCH_EDIT_FRAME : public SCH_BASE_FRAME
     friend class SCH_EDITOR_CONTROL;
 
 private:
+    SCHEMATIC*              m_schematic;          ///< The currently loaded schematic
     wxString                m_SelectedNetName;
 
     std::vector<PARAM_CFG*> m_projectFileParams;
@@ -185,6 +187,8 @@ public:
 
     SCH_SCREEN* GetScreen() const override;
 
+    SCHEMATIC& Schematic() const;
+
     void OnCloseWindow( wxCloseEvent& Event );
 
     /**
@@ -506,11 +510,8 @@ public:
      */
     int ModalAnnotate( const wxString& aMessage );
 
-    ///> @copydoc EDA_BASE_FRAME::GetSeverity()
-    int GetSeverity( int aErrorCode ) const override;
-
     // Functions used for hierarchy handling
-    SCH_SHEET_PATH& GetCurrentSheet();
+    SCH_SHEET_PATH& GetCurrentSheet() const;
 
     void SetCurrentSheet( const SCH_SHEET_PATH& aSheet );
 
@@ -691,6 +692,12 @@ private:
      */
     bool importFile( const wxString& aFileName, int aFileType );
 
+    /**
+     * Fills a map of uuid -> reference from the currently loaded schematic
+     * @param aMap is a map to fill
+     */
+    void mapExistingAnnotation( std::map<wxString, wxString>& aMap );
+
 public:
     /**
      * Verify that \a aSheet will not cause a recursion error in \a aHierarchy.
@@ -984,6 +991,8 @@ public:
 
     void FixupJunctions();
 
+    void FocusOnItem( SCH_ITEM* aItem );
+
     /**
      * Convert sheet and symbol legacy time stamp UUIDs to full UUIDs.
      *
diff --git a/eeschema/sch_field.cpp b/eeschema/sch_field.cpp
index 96d9c3c8cc..c8c04ab832 100644
--- a/eeschema/sch_field.cpp
+++ b/eeschema/sch_field.cpp
@@ -43,6 +43,7 @@
 #include <class_library.h>
 #include <sch_component.h>
 #include <sch_field.h>
+#include <schematic.h>
 #include <settings/color_settings.h>
 #include <kicad_string.h>
 #include <trace_helpers.h>
@@ -120,8 +121,8 @@ wxString SCH_FIELD::GetShownText( int aDepth ) const
 
     if( processTextVars )
     {
-        if( g_RootSheet && g_RootSheet->GetScreen() )
-            project = &g_RootSheet->GetScreen()->Kiway().Prj();
+        if( Schematic() )
+            project = &Schematic()->RootScreen()->Kiway().Prj();
 
         if( aDepth < 10 )
         {
diff --git a/eeschema/sch_io_mgr.h b/eeschema/sch_io_mgr.h
index fe2edd9ff4..94c121e133 100644
--- a/eeschema/sch_io_mgr.h
+++ b/eeschema/sch_io_mgr.h
@@ -32,6 +32,7 @@
 class SCH_SHEET;
 class SCH_SCREEN;
 class SCH_PLUGIN;
+class SCHEMATIC;
 class KIWAY;
 class LIB_PART;
 class PART_LIB;
@@ -208,7 +209,7 @@ public:
      *                 wrong, using line number and character offsets of the input file if
      *                 possible.
      */
-    virtual SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway,
+    virtual SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway, SCHEMATIC* aSchematic,
                              SCH_SHEET* aAppendToMe = NULL, const PROPERTIES* aProperties = NULL );
 
     /**
diff --git a/eeschema/sch_item.cpp b/eeschema/sch_item.cpp
index 090275007c..7cc8347df0 100644
--- a/eeschema/sch_item.cpp
+++ b/eeschema/sch_item.cpp
@@ -35,6 +35,7 @@
 #include <sch_component.h>
 #include <sch_sheet.h>
 #include <sch_pin.h>
+#include <schematic.h>
 #include <general.h>
 
 
@@ -46,9 +47,8 @@
 SCH_ITEM::SCH_ITEM( EDA_ITEM* aParent, KICAD_T aType ) :
     EDA_ITEM( aParent, aType )
 {
-    m_Layer = LAYER_WIRE; // It's only a default, in fact
-    m_fieldsAutoplaced = FIELDS_AUTOPLACED_NO;
-
+    m_Layer              = LAYER_WIRE; // It's only a default, in fact
+    m_fieldsAutoplaced   = FIELDS_AUTOPLACED_NO;
     m_connectivity_dirty = true;
 }
 
@@ -56,9 +56,8 @@ SCH_ITEM::SCH_ITEM( EDA_ITEM* aParent, KICAD_T aType ) :
 SCH_ITEM::SCH_ITEM( const SCH_ITEM& aItem ) :
     EDA_ITEM( aItem )
 {
-    m_Layer = aItem.m_Layer;
-    m_fieldsAutoplaced = aItem.m_fieldsAutoplaced;
-
+    m_Layer              = aItem.m_Layer;
+    m_fieldsAutoplaced   = aItem.m_fieldsAutoplaced;
     m_connectivity_dirty = true;
 }
 
@@ -111,6 +110,22 @@ SCH_ITEM* SCH_ITEM::Duplicate( bool doClone ) const
 }
 
 
+SCHEMATIC* SCH_ITEM::Schematic() const
+{
+    EDA_ITEM* parent = GetParent();
+
+    while( parent )
+    {
+        if( parent->Type() == SCHEMATIC_T )
+            return static_cast<SCHEMATIC*>( parent );
+        else
+            parent = parent->GetParent();
+    }
+
+    return nullptr;
+}
+
+
 void SCH_ITEM::ViewGetLayers( int aLayers[], int& aCount ) const
 {
     // Basic fallback
diff --git a/eeschema/sch_item.h b/eeschema/sch_item.h
index 6d516dfafb..02aad8d75f 100644
--- a/eeschema/sch_item.h
+++ b/eeschema/sch_item.h
@@ -36,6 +36,7 @@
 
 class SCH_CONNECTION;
 class SCH_SHEET_PATH;
+class SCHEMATIC;
 class LINE_READER;
 class SCH_EDIT_FRAME;
 class wxFindReplaceData;
@@ -208,6 +209,19 @@ public:
     wxPoint& GetStoredPos() { return m_storedPos; }
     void     SetStoredPos( wxPoint aPos ) { m_storedPos = aPos; }
 
+    /**
+     * Searches the item hierarchy to find a SCHEMATIC
+     *
+     * Every SCH_ITEM that lives on a SCH_SCREEN should be parented to either that screen
+     * or another SCH_ITEM on the same screen (for example, pins to their components).
+     *
+     * Every SCH_SCREEN should be parented to the SCHEMATIC.
+     * Note that this hierarchy is not the same as the sheet hierarchy!
+     *
+     * @return the parent schematic this item lives on, or nullptr
+     */
+    SCHEMATIC* Schematic() const;
+
     /**
      * Function IsLocked
      * @return bool - true if the object is locked, else false
diff --git a/eeschema/sch_legacy_plugin.cpp b/eeschema/sch_legacy_plugin.cpp
index d9d1a1e989..73aa54b3ed 100644
--- a/eeschema/sch_legacy_plugin.cpp
+++ b/eeschema/sch_legacy_plugin.cpp
@@ -53,6 +53,7 @@
 #include <sch_legacy_plugin.h>
 #include <template_fieldnames.h>
 #include <sch_screen.h>
+#include <schematic.h>
 #include <class_libentry.h>
 #include <class_library.h>
 #include <lib_arc.h>
@@ -586,7 +587,7 @@ void SCH_LEGACY_PLUGIN::init( KIWAY* aKiway, const PROPERTIES* aProperties )
 }
 
 
-SCH_SHEET* SCH_LEGACY_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway,
+SCH_SHEET* SCH_LEGACY_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCHEMATIC* aSchematic,
                                     SCH_SHEET* aAppendToMe, const PROPERTIES* aProperties )
 {
     wxASSERT( !aFileName || aKiway != NULL );
@@ -594,6 +595,8 @@ SCH_SHEET* SCH_LEGACY_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway,
     LOCALE_IO   toggle;     // toggles on, then off, the C locale.
     SCH_SHEET*  sheet;
 
+    m_schematic = aSchematic;
+
     wxFileName fn = aFileName;
 
     // Unfortunately child sheet file names the legacy schematic file format are not fully
@@ -630,7 +633,7 @@ SCH_SHEET* SCH_LEGACY_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway,
     if( aAppendToMe == NULL )
     {
         // Clean up any allocated memory if an exception occurs loading the schematic.
-        std::unique_ptr< SCH_SHEET > newSheet( new SCH_SHEET );
+        std::unique_ptr< SCH_SHEET > newSheet( new SCH_SHEET( aSchematic ) );
         newSheet->SetFileName( aFileName );
         m_rootSheet = newSheet.get();
         loadHierarchy( newSheet.get() );
@@ -640,8 +643,8 @@ SCH_SHEET* SCH_LEGACY_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway,
     }
     else
     {
-        m_rootSheet = aAppendToMe->GetRootSheet();
-        wxASSERT( m_rootSheet );
+        wxCHECK_MSG( aSchematic->IsValid(), nullptr, "Can't append to a schematic with no root!" );
+        m_rootSheet = &aSchematic->Root();
         sheet = aAppendToMe;
         loadHierarchy( sheet );
     }
@@ -682,13 +685,14 @@ void SCH_LEGACY_PLUGIN::loadHierarchy( SCH_SHEET* aSheet )
         if( screen )
         {
             aSheet->SetScreen( screen );
-
+            screen->SetParent( m_schematic );
             // Do not need to load the sub-sheets - this has already been done.
         }
         else
         {
             aSheet->SetScreen( new SCH_SCREEN( m_kiway ) );
             aSheet->GetScreen()->SetFileName( fileName.GetFullPath() );
+            aSheet->GetScreen()->SetParent( m_schematic );
 
             try
             {
@@ -757,10 +761,9 @@ void SCH_LEGACY_PLUGIN::LoadContent( LINE_READER& aReader, SCH_SCREEN* aScreen,
 {
     m_version = version;
 
-    // We cannot safely load content without a set root level.  If we haven't been given one,
-    // pick the default
-    if( m_rootSheet == nullptr )
-        m_rootSheet = g_RootSheet;
+    // We cannot safely load content without a set root level.
+    wxCHECK_RET( m_rootSheet,
+            "Cannot call SCH_LEGACY_PLUGIN::LoadContent() without setting root sheet." );
 
     while( aReader.ReadLine() )
     {
diff --git a/eeschema/sch_legacy_plugin.h b/eeschema/sch_legacy_plugin.h
index ded4bf81a5..7ca7e7fbf4 100644
--- a/eeschema/sch_legacy_plugin.h
+++ b/eeschema/sch_legacy_plugin.h
@@ -97,7 +97,7 @@ public:
 
     int GetModifyHash() const override;
 
-    SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway,
+    SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway , SCHEMATIC* aSchematic,
                      SCH_SHEET* aAppendToMe = nullptr,
                      const PROPERTIES* aProperties = nullptr ) override;
 
@@ -181,6 +181,7 @@ protected:
     SCH_SHEET*           m_rootSheet;  ///< The root sheet of the schematic being loaded..
     OUTPUTFORMATTER*     m_out;        ///< The output formatter for saving SCH_SCREEN objects.
     SCH_LEGACY_PLUGIN_CACHE* m_cache;
+    SCHEMATIC*          m_schematic;   ///< Passed to Load(), the schematic object being loaded
 
     /// initialize PLUGIN like a constructor would.
     void init( KIWAY* aKiway, const PROPERTIES* aProperties = nullptr );
diff --git a/eeschema/sch_line.cpp b/eeschema/sch_line.cpp
index ed6e71498e..9b63a9fcf6 100644
--- a/eeschema/sch_line.cpp
+++ b/eeschema/sch_line.cpp
@@ -791,7 +791,12 @@ void SCH_LINE::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, MSG_PANEL_ITEMS& aList )
 
     aList.push_back( MSG_PANEL_ITEM( _( "Line Type" ), msg, DARKCYAN ) );
 
-    if( auto conn = Connection( *g_CurrentSheet ) )
+    SCH_EDIT_FRAME* frame = dynamic_cast<SCH_EDIT_FRAME*>( aFrame );
+
+    if( !frame )
+        return;
+
+    if( auto conn = Connection( frame->GetCurrentSheet() ) )
     {
 #if defined(DEBUG)
         conn->AppendDebugInfoToMsgPanel( aList );
diff --git a/eeschema/sch_marker.cpp b/eeschema/sch_marker.cpp
index f91b8f8b9e..642ee4f362 100644
--- a/eeschema/sch_marker.cpp
+++ b/eeschema/sch_marker.cpp
@@ -29,6 +29,7 @@
 #include <bitmaps.h>
 #include <base_units.h>
 #include <sch_marker.h>
+#include <schematic.h>
 #include <widgets/ui_common.h>
 #include <pgm_base.h>
 #include <settings/settings_manager.h>
@@ -75,9 +76,11 @@ void SCH_MARKER::Show( int nestLevel, std::ostream& os ) const
 
 void SCH_MARKER::ViewGetLayers( int aLayers[], int& aCount ) const
 {
-    aCount     = 2;
+    aCount = 2;
 
-    switch( GetSeverity( m_rcItem->GetErrorCode() ) )
+    wxCHECK_RET( Schematic(), "No SCHEMATIC set for SCH_MARKER!" );
+
+    switch( Schematic()->GetErcSeverity( m_rcItem->GetErrorCode() ) )
     {
     default:
     case SEVERITY::RPT_SEVERITY_ERROR:   aLayers[0] = LAYER_ERC_ERR;  break;
@@ -93,7 +96,9 @@ SCH_LAYER_ID SCH_MARKER::GetColorLayer() const
     if( IsExcluded() )
         return LAYER_HIDDEN;
 
-    switch( GetSeverity( m_rcItem->GetErrorCode() ) )
+    wxCHECK_MSG( Schematic(), LAYER_ERC_ERR, "No SCHEMATIC set for SCH_MARKER!" );
+
+    switch( Schematic()->GetErcSeverity( m_rcItem->GetErrorCode() ) )
     {
     default:
     case SEVERITY::RPT_SEVERITY_ERROR:   return LAYER_ERC_ERR;
diff --git a/eeschema/sch_painter.cpp b/eeschema/sch_painter.cpp
index 964c2d8c10..5d7591ca12 100644
--- a/eeschema/sch_painter.cpp
+++ b/eeschema/sch_painter.cpp
@@ -57,6 +57,7 @@
 #include <sch_no_connect.h>
 #include <sch_sheet.h>
 #include <sch_text.h>
+#include <schematic.h>
 #include <settings/color_settings.h>
 #include <view/view.h>
 #include <kiface_i.h>
@@ -150,7 +151,8 @@ static LIB_PART* dummy()
 
 
 SCH_PAINTER::SCH_PAINTER( GAL* aGal ) :
-    KIGFX::PAINTER( aGal )
+    KIGFX::PAINTER( aGal ),
+    m_schematic( nullptr )
 { }
 
 
@@ -1267,11 +1269,15 @@ void SCH_PAINTER::draw( SCH_TEXT *aText, int aLayer )
     default:                  aLayer = LAYER_NOTES;      break;
     }
 
-    COLOR4D         color = getRenderColor( aText, aLayer, drawingShadows );
-    SCH_CONNECTION* conn = aText->Connection( *g_CurrentSheet );
+    COLOR4D color = getRenderColor( aText, aLayer, drawingShadows );
 
-    if( conn && conn->IsBus() )
-        color = getRenderColor( aText, LAYER_BUS, drawingShadows );
+    if( m_schematic )
+    {
+        SCH_CONNECTION* conn = aText->Connection( m_schematic->CurrentSheet() );
+
+        if( conn && conn->IsBus() )
+            color = getRenderColor( aText, LAYER_BUS, drawingShadows );
+    }
 
     if( !( aText->IsVisible() || aText->IsForceVisible() ) )
     {
@@ -1565,10 +1571,13 @@ void SCH_PAINTER::draw( SCH_HIERLABEL *aLabel, int aLayer )
 
     COLOR4D color = getRenderColor( aLabel, LAYER_SHEETLABEL, drawingShadows );
 
-    SCH_CONNECTION* conn = aLabel->Connection( *g_CurrentSheet );
+    if( m_schematic )
+    {
+        SCH_CONNECTION* conn = aLabel->Connection( m_schematic->CurrentSheet() );
 
-    if( conn && conn->IsBus() )
-        color = getRenderColor( aLabel, LAYER_BUS, drawingShadows );
+        if( conn && conn->IsBus() )
+            color = getRenderColor( aLabel, LAYER_BUS, drawingShadows );
+    }
 
     std::vector<wxPoint> pts;
     std::deque<VECTOR2D> pts2;
diff --git a/eeschema/sch_painter.h b/eeschema/sch_painter.h
index 9a422ee867..ee84eb7c4a 100644
--- a/eeschema/sch_painter.h
+++ b/eeschema/sch_painter.h
@@ -54,6 +54,7 @@ class SCH_NO_CONNECT;
 class SCH_LINE;
 class SCH_BUS_ENTRY_BASE;
 class SCH_BITMAP;
+class SCHEMATIC;
 
 namespace KIGFX
 {
@@ -143,6 +144,11 @@ public:
         return &m_schSettings;
     }
 
+    void SetSchematic( SCHEMATIC* aSchematic )
+    {
+        m_schematic = aSchematic;
+    }
+
 private:
 	void draw( LIB_RECTANGLE* aRect, int aLayer );
 	void draw( LIB_PIN* aPin, int aLayer );
@@ -190,6 +196,8 @@ private:
     void strokeText( const wxString& aText, const VECTOR2D& aPosition, double aRotationAngle );
 
     SCH_RENDER_SETTINGS m_schSettings;
+
+    SCHEMATIC* m_schematic;
 };
 
 }; // namespace KIGFX
diff --git a/eeschema/sch_plugin.cpp b/eeschema/sch_plugin.cpp
index 8b9f96039c..5ae9e351fa 100644
--- a/eeschema/sch_plugin.cpp
+++ b/eeschema/sch_plugin.cpp
@@ -47,8 +47,8 @@ void SCH_PLUGIN::SaveLibrary( const wxString& aFileName, const PROPERTIES* aProp
 }
 
 
-SCH_SHEET* SCH_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCH_SHEET* aAppendToMe,
-                             const PROPERTIES* aProperties )
+SCH_SHEET* SCH_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCHEMATIC* aSchematic,
+                             SCH_SHEET* aAppendToMe, const PROPERTIES* aProperties )
 {
     not_implemented( this, __FUNCTION__ );
     return NULL;
diff --git a/eeschema/sch_screen.cpp b/eeschema/sch_screen.cpp
index 74c716dba8..9e85d63658 100644
--- a/eeschema/sch_screen.cpp
+++ b/eeschema/sch_screen.cpp
@@ -55,6 +55,7 @@
 #include <sch_marker.h>
 #include <sch_sheet.h>
 #include <sch_text.h>
+#include <schematic.h>
 #include <symbol_lib_table.h>
 #include <tool/common_tools.h>
 
@@ -154,6 +155,15 @@ SCH_SCREEN::~SCH_SCREEN()
 }
 
 
+SCHEMATIC* SCH_SCREEN::Schematic() const
+{
+    wxCHECK_MSG( GetParent() && GetParent()->Type() == SCHEMATIC_T, nullptr,
+            "SCH_SCREEN must have a SCHEMATIC parent!" );
+
+    return static_cast<SCHEMATIC*>( GetParent() );
+}
+
+
 void SCH_SCREEN::clearLibSymbols()
 {
     for( auto libSymbol : m_libSymbols )
@@ -187,6 +197,9 @@ bool SCH_SCREEN::HasItems( KICAD_T aItemType ) const
 
 void SCH_SCREEN::Append( SCH_ITEM* aItem )
 {
+    // Ensure the item can reach the SCHEMATIC through this screen
+    aItem->SetParent( this );
+
     if( aItem->Type() != SCH_SHEET_PIN_T && aItem->Type() != SCH_FIELD_T )
     {
         if( aItem->Type() == SCH_COMPONENT_T )
@@ -1178,42 +1191,6 @@ void SCH_SCREEN::AddBusAlias( std::shared_ptr<BUS_ALIAS> aAlias )
 }
 
 
-bool SCH_SCREEN::IsBusAlias( const wxString& aLabel )
-{
-    SCH_SHEET_LIST aSheets( g_RootSheet );
-    for( unsigned i = 0; i < aSheets.size(); i++ )
-    {
-        for( const auto& alias : aSheets[i].LastScreen()->GetBusAliases() )
-        {
-            if( alias->GetName() == aLabel )
-            {
-                return true;
-            }
-        }
-    }
-
-    return false;
-}
-
-
-std::shared_ptr<BUS_ALIAS> SCH_SCREEN::GetBusAlias( const wxString& aLabel )
-{
-    SCH_SHEET_LIST aSheets( g_RootSheet );
-    for( unsigned i = 0; i < aSheets.size(); i++ )
-    {
-        for( auto alias : aSheets[i].LastScreen()->GetBusAliases() )
-        {
-            if( alias->GetName() == aLabel )
-            {
-                return alias;
-            }
-        }
-    }
-
-    return NULL;
-}
-
-
 #if defined(DEBUG)
 void SCH_SCREEN::Show( int nestLevel, std::ostream& os ) const
 {
@@ -1231,7 +1208,7 @@ void SCH_SCREEN::Show( int nestLevel, std::ostream& os ) const
 SCH_SCREENS::SCH_SCREENS( SCH_SHEET* aSheet )
 {
     m_index = 0;
-    buildScreenList( ( !aSheet ) ? g_RootSheet : aSheet );
+    buildScreenList( aSheet );
 }
 
 
@@ -1317,16 +1294,18 @@ void SCH_SCREENS::ClearAnnotation()
 
 void SCH_SCREENS::ClearAnnotationOfNewSheetPaths( SCH_SHEET_LIST& aInitialSheetPathList )
 {
+    SCHEMATIC* sch = GetFirst()->Schematic();
+
+    wxCHECK_RET( sch, "Null schematic in SCH_SCREENS::ClearAnnotationOfNewSheetPaths" );
+
     // Clear the annotation for the components inside new sheetpaths
     // not already in aInitialSheetList
-    SCH_SCREENS screensList( g_RootSheet );     // The list of screens, shared by sheet paths
+    SCH_SCREENS screensList( sch->Root() );     // The list of screens, shared by sheet paths
     screensList.BuildClientSheetPathList();     // build the shared by sheet paths, by screen
 
     // Search for new sheet paths, not existing in aInitialSheetPathList
     // and existing in sheetpathList
-    SCH_SHEET_LIST sheetpathList( g_RootSheet );
-
-    for( SCH_SHEET_PATH& sheetpath: sheetpathList )
+    for( SCH_SHEET_PATH& sheetpath : sch->GetSheets() )
     {
         bool path_exists = false;
 
@@ -1440,12 +1419,16 @@ void SCH_SCREENS::UpdateSymbolLinks( REPORTER* aReporter )
     for( SCH_SCREEN* screen = GetFirst(); screen; screen = GetNext() )
         screen->UpdateSymbolLinks( aReporter );
 
-    SCH_SHEET_LIST sheets( g_RootSheet );
+    SCHEMATIC* sch = GetFirst()->Schematic();
+
+    wxCHECK_RET( sch, "Null schematic in SCH_SCREENS::UpdateSymbolLinks" );
+
+    SCH_SHEET_LIST sheets = sch->GetSheets();
 
     // All of the library symbols have been replaced with copies so the connection graph
     // pointer are stale.
-    if( g_ConnectionGraph )
-        g_ConnectionGraph->Recalculate( sheets, true );
+    if( sch->ConnectionGraph() )
+        sch->ConnectionGraph()->Recalculate( sheets, true );
 }
 
 
@@ -1588,12 +1571,14 @@ bool SCH_SCREENS::CanCauseCaseSensitivityIssue( const wxString& aSchematicFileNa
 
 void SCH_SCREENS::BuildClientSheetPathList()
 {
-    SCH_SHEET_LIST sheetList( g_RootSheet );
+    SCHEMATIC* sch = GetFirst()->Schematic();
+
+    wxCHECK_RET( sch, "Null schematic in SCH_SCREENS::BuildClientSheetPathList" );
 
     for( SCH_SCREEN* curr_screen = GetFirst(); curr_screen; curr_screen = GetNext() )
         curr_screen->GetClientSheetPaths().clear();
 
-    for( SCH_SHEET_PATH& sheetpath: sheetList )
+    for( SCH_SHEET_PATH& sheetpath : sch->GetSheets() )
     {
         SCH_SCREEN* used_screen = sheetpath.LastScreen();
 
diff --git a/eeschema/sch_screen.h b/eeschema/sch_screen.h
index b58f38344f..3883da9ede 100644
--- a/eeschema/sch_screen.h
+++ b/eeschema/sch_screen.h
@@ -157,6 +157,8 @@ public:
 
     ~SCH_SCREEN();
 
+    SCHEMATIC* Schematic() const;
+
     EE_RTREE& Items()
     {
         return m_rtree;
@@ -534,17 +536,6 @@ public:
         return m_aliases;
     }
 
-    /**
-     * Returns true if the given string is a valid bus alias in a loaded screen
-     */
-    static bool IsBusAlias( const wxString& aLabel );
-
-    /**
-     * Returns a pointer to a bus alias object for the given label,
-     * or null if one doesn't exist
-     */
-    static std::shared_ptr<BUS_ALIAS> GetBusAlias( const wxString& aLabel );
-
 #if defined(DEBUG)
     void Show( int nestLevel, std::ostream& os ) const override;
 #endif
@@ -555,6 +546,10 @@ public:
  * Container class that holds multiple #SCH_SCREEN objects in a hierarchy.
  *
  * Individual #SCH_SCREEN objects are unique and correspond to .sch files.
+ *
+ * NOTE: It may be desirable to fold the functionality of SCH_SCREENS into
+ * the new SCHEMATIC class at some point, since SCHEMATIC can also be thought
+ * of as owning the collection of all the SCH_SCREEN objects.
  */
 class SCH_SCREENS
 {
@@ -564,7 +559,8 @@ private:
     unsigned int               m_index;
 
 public:
-    SCH_SCREENS( SCH_SHEET* aSheet = NULL );
+    SCH_SCREENS( SCH_SHEET* aSheet );
+    SCH_SCREENS( SCH_SHEET& aSheet ) : SCH_SCREENS( &aSheet ) {}
     ~SCH_SCREENS();
     size_t GetCount() const { return m_screens.size(); }
     SCH_SCREEN* GetFirst();
diff --git a/eeschema/sch_sexpr_plugin.cpp b/eeschema/sch_sexpr_plugin.cpp
index a6b807903c..9bb336791a 100644
--- a/eeschema/sch_sexpr_plugin.cpp
+++ b/eeschema/sch_sexpr_plugin.cpp
@@ -54,6 +54,7 @@
 #include <sch_text.h>
 #include <sch_sheet.h>
 #include <sch_bitmap.h>
+#include <schematic.h>
 #include <bus_alias.h>
 #include <sch_sexpr_plugin.h>
 #include <template_fieldnames.h>
@@ -418,7 +419,7 @@ void SCH_SEXPR_PLUGIN::init( KIWAY* aKiway, const PROPERTIES* aProperties )
 }
 
 
-SCH_SHEET* SCH_SEXPR_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway,
+SCH_SHEET* SCH_SEXPR_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway, SCHEMATIC* aSchematic,
                                    SCH_SHEET* aAppendToMe, const PROPERTIES* aProperties )
 {
     wxASSERT( !aFileName || aKiway != NULL );
@@ -459,10 +460,12 @@ SCH_SHEET* SCH_SEXPR_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway,
     m_currentPath.push( m_path );
     init( aKiway, aProperties );
 
+    m_schematic = aSchematic;
+
     if( aAppendToMe == NULL )
     {
         // Clean up any allocated memory if an exception occurs loading the schematic.
-        std::unique_ptr< SCH_SHEET > newSheet( new SCH_SHEET );
+        std::unique_ptr< SCH_SHEET > newSheet( new SCH_SHEET( aSchematic ) );
         newSheet->SetFileName( aFileName );
         m_rootSheet = newSheet.get();
         loadHierarchy( newSheet.get() );
@@ -473,8 +476,8 @@ SCH_SHEET* SCH_SEXPR_PLUGIN::Load( const wxString& aFileName, KIWAY* aKiway,
     }
     else
     {
-        m_rootSheet = aAppendToMe->GetRootSheet();
-        wxASSERT( m_rootSheet != NULL );
+        wxCHECK_MSG( aSchematic->IsValid(), nullptr, "Can't append to a schematic with no root!" );
+        m_rootSheet = &aSchematic->Root();
         sheet = aAppendToMe;
         loadHierarchy( sheet );
     }
@@ -514,13 +517,14 @@ void SCH_SEXPR_PLUGIN::loadHierarchy( SCH_SHEET* aSheet )
         if( screen )
         {
             aSheet->SetScreen( screen );
-
+            aSheet->GetScreen()->SetParent( m_schematic );
             // Do not need to load the sub-sheets - this has already been done.
         }
         else
         {
             aSheet->SetScreen( new SCH_SCREEN( m_kiway ) );
             aSheet->GetScreen()->SetFileName( fileName.GetFullPath() );
+            aSheet->GetScreen()->SetParent( m_schematic );
 
             try
             {
diff --git a/eeschema/sch_sexpr_plugin.h b/eeschema/sch_sexpr_plugin.h
index 2384a6add5..0d1877eb9e 100644
--- a/eeschema/sch_sexpr_plugin.h
+++ b/eeschema/sch_sexpr_plugin.h
@@ -84,7 +84,7 @@ public:
 
     int GetModifyHash() const override;
 
-    SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway,
+    SCH_SHEET* Load( const wxString& aFileName, KIWAY* aKiway, SCHEMATIC* aSchematic,
                      SCH_SHEET* aAppendToMe = nullptr,
                      const PROPERTIES* aProperties = nullptr ) override;
 
@@ -156,6 +156,7 @@ protected:
     const PROPERTIES*    m_props;      ///< Passed via Save() or Load(), no ownership, may be nullptr.
     KIWAY*               m_kiway;      ///< Required for path to legacy component libraries.
     SCH_SHEET*           m_rootSheet;  ///< The root sheet of the schematic being loaded..
+    SCHEMATIC*           m_schematic;  ///< Passed to Load(), the schematic object being loaded
     OUTPUTFORMATTER*     m_out;        ///< The output formatter for saving SCH_SCREEN objects.
     SCH_SEXPR_PLUGIN_CACHE* m_cache;
 
diff --git a/eeschema/sch_sheet.cpp b/eeschema/sch_sheet.cpp
index 0949b009d5..9823de4f53 100644
--- a/eeschema/sch_sheet.cpp
+++ b/eeschema/sch_sheet.cpp
@@ -34,6 +34,7 @@
 #include <sch_sheet.h>
 #include <sch_sheet_path.h>
 #include <sch_component.h>
+#include <schematic.h>
 #include <settings/color_settings.h>
 #include <netlist_object.h>
 #include <trace_helpers.h>
@@ -67,8 +68,8 @@ const wxString SCH_SHEET::GetDefaultFieldName( int aFieldNdx )
 }
 
 
-SCH_SHEET::SCH_SHEET( const wxPoint& pos ) :
-    SCH_ITEM( NULL, SCH_SHEET_T )
+SCH_SHEET::SCH_SHEET( EDA_ITEM* aParent, const wxPoint& pos ) :
+    SCH_ITEM( aParent, SCH_SHEET_T )
 {
     m_Layer = LAYER_SHEET;
     m_pos = pos;
@@ -146,19 +147,6 @@ EDA_ITEM* SCH_SHEET::Clone() const
 }
 
 
-void SCH_SHEET::SetParent( EDA_ITEM* aSheet )
-{
-    m_Parent = nullptr;
-
-    if( aSheet )
-    {
-        // Parent must be another SCH_SHEET object or nullptr
-        wxCHECK( aSheet->Type() == SCH_SHEET_T, /* void */ );
-        m_Parent = aSheet;
-    }
-}
-
-
 void SCH_SHEET::SetScreen( SCH_SCREEN* aScreen )
 {
     if( aScreen == m_screen )
@@ -191,20 +179,11 @@ int SCH_SHEET::GetScreenCount() const
 }
 
 
-SCH_SHEET* SCH_SHEET::GetRootSheet()
+bool SCH_SHEET::IsRootSheet() const
 {
-    EDA_ITEM* item = GetParent();
+    wxCHECK_MSG( Schematic(), false, "Can't call IsRootSheet without setting a schematic" );
 
-    if( item == nullptr )
-        return this;
-
-    SCH_SHEET* sheet = dynamic_cast< SCH_SHEET* >( item );
-
-    // The parent must be a SCH_SHEET object.
-    wxCHECK( sheet, nullptr );
-
-    // Recurse until a sheet is found with no parent which is the root sheet.
-    return sheet->GetRootSheet();
+    return &Schematic()->Root() == this;
 }
 
 
@@ -230,9 +209,7 @@ bool SCH_SHEET::ResolveTextVar( wxString* token, int aDepth ) const
 
     if( token->IsSameAs( wxT( "#" ) ) )
     {
-        SCH_SHEET_LIST sheetList( g_RootSheet );
-
-        for( const SCH_SHEET_PATH& sheet : sheetList )
+        for( const SCH_SHEET_PATH& sheet : Schematic()->GetSheets() )
         {
             if( sheet.Last() == this )   // Current sheet path found
             {
@@ -243,7 +220,7 @@ bool SCH_SHEET::ResolveTextVar( wxString* token, int aDepth ) const
     }
     else if( token->IsSameAs( wxT( "##" ) ) )
     {
-        SCH_SHEET_LIST sheetList( g_RootSheet );
+        SCH_SHEET_LIST sheetList = Schematic()->GetSheets();
         *token = wxString::Format( wxT( "%d" ), (int) sheetList.size() );
         return true;
     }
@@ -703,7 +680,7 @@ bool SCH_SHEET::LocatePathOfScreen( SCH_SCREEN* aScreen, SCH_SHEET_PATH* aList )
 }
 
 
-int SCH_SHEET::CountSheets()
+int SCH_SHEET::CountSheets() const
 {
     int count = 1; //1 = this!!
 
@@ -723,11 +700,15 @@ void SCH_SHEET::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, MSG_PANEL_ITEMS& aList
     aList.emplace_back( _( "File Name" ), m_fields[ SHEETFILENAME ].GetText(), BROWN );
 
 #if 1   // Set to 1 to display the sheet UUID and hierarchical path
-    wxString msgU, msgL;
-    msgU << _( "UUID" ) << ": " << m_Uuid.AsString();
-    msgL << _( "Path" ) << ": " << g_CurrentSheet->PathHumanReadable();
 
-    aList.push_back( MSG_PANEL_ITEM( msgU, msgL, BLUE ) );
+    if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( aFrame ) )
+    {
+        wxString msgU, msgL;
+        msgU << _( "UUID" ) << ": " << m_Uuid.AsString();
+        msgL << _( "Path" ) << ": " << schframe->GetCurrentSheet().PathHumanReadable();
+
+        aList.push_back( MSG_PANEL_ITEM( msgU, msgL, BLUE ) );
+    }
 #endif
 }
 
diff --git a/eeschema/sch_sheet.h b/eeschema/sch_sheet.h
index de92753dc4..9c77c172d9 100644
--- a/eeschema/sch_sheet.h
+++ b/eeschema/sch_sheet.h
@@ -234,7 +234,7 @@ class SCH_SHEET : public SCH_ITEM
     KIGFX::COLOR4D              m_backgroundColor;
 
 public:
-    SCH_SHEET( const wxPoint& pos = wxPoint( 0, 0 ) );
+    SCH_SHEET( EDA_ITEM* aParent = nullptr, const wxPoint& pos = wxPoint( 0, 0 ) );
 
     /**
      * Copy \a aSheet into a new object.  All sheet pins are copied as is except and
@@ -254,8 +254,6 @@ public:
         return wxT( "SCH_SHEET" );
     }
 
-    virtual void SetParent( EDA_ITEM* aSheet ) override;
-
     /**
      * Return true for items which are moved with the anchor point at mouse cursor
      * and false for items moved with no reference to anchor.
@@ -281,7 +279,7 @@ public:
 
     wxString GetName() const { return m_fields[ SHEETNAME ].GetText(); }
 
-    SCH_SCREEN* GetScreen() { return m_screen; }
+    SCH_SCREEN* GetScreen() const { return m_screen; }
 
     wxSize GetSize() { return m_size; }
     void SetSize( const wxSize& aSize ) { m_size = aSize; }
@@ -307,21 +305,10 @@ public:
      */
     bool UsesDefaultStroke() const;
 
-    /**
-     * Return the root sheet of this SCH_SHEET object.
-     *
-     * The root (top level) sheet can be found by walking up the parent links until the only
-     * sheet that has no parent is found.  The root sheet can be found from any sheet without
-     * having to maintain a global root sheet pointer.
-     *
-     * @return a SCH_SHEET pointer to the root sheet.
-     */
-    SCH_SHEET* GetRootSheet();
-
     /**
      * @return true if this sheet is the root sheet.
      */
-    bool IsRootSheet() { return GetRootSheet() == this; }
+    bool IsRootSheet() const;
 
     /**
      * Set the #SCH_SCREEN associated with this sheet to \a aScreen.
@@ -494,7 +481,7 @@ public:
      *
      * @return the full count of sheets+subsheets contained by "this"
      */
-    int CountSheets();
+    int CountSheets() const;
 
     /**
      * Return the filename corresponding to this sheet.
diff --git a/eeschema/sch_sheet_path.cpp b/eeschema/sch_sheet_path.cpp
index ee0b56e414..fe0c7732b0 100644
--- a/eeschema/sch_sheet_path.cpp
+++ b/eeschema/sch_sheet_path.cpp
@@ -33,6 +33,7 @@
 #include <sch_sheet_path.h>
 #include <sch_component.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 #include <template_fieldnames.h>
 #include <trace_helpers.h>
 
@@ -209,7 +210,7 @@ void SCH_SHEET_PATH::GetComponents( SCH_REFERENCE_LIST& aReferences, bool aInclu
 
 
 void SCH_SHEET_PATH::GetMultiUnitComponents( SCH_MULTI_UNIT_REFERENCE_MAP& aRefList,
-                                             bool aIncludePowerSymbols )
+                                             bool aIncludePowerSymbols ) const
 {
     for( auto item : LastScreen()->Items().OfType( SCH_COMPONENT_T ) )
     {
@@ -263,7 +264,11 @@ bool SCH_SHEET_PATH::TestForRecursion( const wxString& aSrcFileName, const wxStr
     if( m_recursion_test_cache.count( pair ) )
         return m_recursion_test_cache.at( pair );
 
-    wxFileName rootFn = g_RootSheet->GetFileName();
+    SCHEMATIC* sch = LastScreen()->Schematic();
+
+    wxCHECK_MSG( sch, false, "No SCHEMATIC found in SCH_SHEET_PATH::TestForRecursion!" );
+
+    wxFileName rootFn = sch->GetFileName();
     wxFileName srcFn = aSrcFileName;
     wxFileName destFn = aDestFileName;
 
@@ -335,8 +340,6 @@ bool SCH_SHEET_PATH::TestForRecursion( const wxString& aSrcFileName, const wxStr
 
 SCH_SHEET_LIST::SCH_SHEET_LIST( SCH_SHEET* aSheet )
 {
-    m_isRootSheet = false;
-
     if( aSheet != NULL )
         BuildSheetList( aSheet );
 }
@@ -348,9 +351,6 @@ void SCH_SHEET_LIST::BuildSheetList( SCH_SHEET* aSheet )
 
     std::vector<SCH_SHEET*> badSheets;
 
-    if( aSheet == g_RootSheet )
-        m_isRootSheet = true;
-
     m_currentSheetPath.push_back( aSheet );
 
     /**
@@ -432,7 +432,9 @@ SCH_ITEM* SCH_SHEET_LIST::GetItem( const KIID& aID, SCH_SHEET_PATH* aPathOut )
         {
             if( aItem->m_Uuid == aID )
             {
-                *aPathOut = sheet;
+                if( aPathOut )
+                    *aPathOut = sheet;
+
                 return aItem;
             }
             else if( aItem->Type() == SCH_COMPONENT_T )
@@ -443,7 +445,9 @@ SCH_ITEM* SCH_SHEET_LIST::GetItem( const KIID& aID, SCH_SHEET_PATH* aPathOut )
                 {
                     if( field.m_Uuid == aID )
                     {
-                        *aPathOut = sheet;
+                        if( aPathOut )
+                            *aPathOut = sheet;
+
                         return &field;
                     }
                 }
@@ -452,7 +456,9 @@ SCH_ITEM* SCH_SHEET_LIST::GetItem( const KIID& aID, SCH_SHEET_PATH* aPathOut )
                 {
                     if( pin->m_Uuid == aID )
                     {
-                        *aPathOut = sheet;
+                        if( aPathOut )
+                            *aPathOut = sheet;
+
                         return pin;
                     }
                 }
@@ -465,7 +471,8 @@ SCH_ITEM* SCH_SHEET_LIST::GetItem( const KIID& aID, SCH_SHEET_PATH* aPathOut )
                 {
                     if( field.m_Uuid == aID )
                     {
-                        *aPathOut = sheet;
+                        if( aPathOut )
+                            *aPathOut = sheet;
                         return &field;
                     }
                 }
@@ -474,7 +481,9 @@ SCH_ITEM* SCH_SHEET_LIST::GetItem( const KIID& aID, SCH_SHEET_PATH* aPathOut )
                 {
                     if( pin->m_Uuid == aID )
                     {
-                        *aPathOut = sheet;
+                        if( aPathOut )
+                            *aPathOut = sheet;
+
                         return pin;
                     }
                 }
@@ -595,16 +604,17 @@ void SCH_SHEET_LIST::AnnotatePowerSymbols()
 
 
 void SCH_SHEET_LIST::GetComponents( SCH_REFERENCE_LIST& aReferences, bool aIncludePowerSymbols,
-                                    bool aForceIncludeOrphanComponents )
+                                    bool aForceIncludeOrphanComponents ) const
 {
-    for( SCH_SHEET_PATH& sheet : *this )
+    for( const SCH_SHEET_PATH& sheet : *this )
         sheet.GetComponents( aReferences, aIncludePowerSymbols, aForceIncludeOrphanComponents );
 }
 
+
 void SCH_SHEET_LIST::GetMultiUnitComponents( SCH_MULTI_UNIT_REFERENCE_MAP &aRefList,
-                                             bool aIncludePowerSymbols )
+                                             bool aIncludePowerSymbols ) const
 {
-    for( SCH_SHEET_PATHS_ITER it = begin(); it != end(); ++it )
+    for( SCH_SHEET_PATHS::const_iterator it = begin(); it != end(); ++it )
     {
         SCH_MULTI_UNIT_REFERENCE_MAP tempMap;
         (*it).GetMultiUnitComponents( tempMap );
@@ -638,7 +648,14 @@ bool SCH_SHEET_LIST::SetComponentFootprint( const wxString& aReference,
 bool SCH_SHEET_LIST::TestForRecursion( const SCH_SHEET_LIST& aSrcSheetHierarchy,
                                        const wxString& aDestFileName )
 {
-    wxFileName rootFn = g_RootSheet->GetFileName();
+    if( empty() )
+        return false;
+
+    SCHEMATIC* sch = at( 0 ).LastScreen()->Schematic();
+
+    wxCHECK_MSG( sch, false, "No SCHEMATIC found in SCH_SHEET_LIST::TestForRecursion!" );
+
+    wxFileName rootFn = sch->GetFileName();
     wxFileName destFn = aDestFileName;
 
     if( destFn.IsRelative() )
@@ -681,8 +698,6 @@ SCH_SHEET_PATH* SCH_SHEET_LIST::FindSheetForScreen( SCH_SCREEN* aScreen )
 void SCH_SHEET_LIST::UpdateSymbolInstances(
         std::vector<COMPONENT_INSTANCE_REFERENCE>& aSymbolInstances )
 {
-    wxCHECK( m_isRootSheet, /* void */ );   // Only performed for the entire schematic.
-
     SCH_REFERENCE_LIST symbolInstances;
 
     GetComponents( symbolInstances, true, true );
@@ -749,95 +764,3 @@ void SCH_SHEET_LIST::ReplaceLegacySheetPaths( const std::vector<KIID_PATH>& aOld
         }
     }
 }
-
-
-void SHEETLIST_ERC_ITEMS_PROVIDER::SetSeverities( int aSeverities )
-{
-    m_severities = aSeverities;
-
-    m_filteredMarkers.clear();
-
-    SCH_SHEET_LIST sheetList( g_RootSheet);
-
-    for( unsigned i = 0; i < sheetList.size(); i++ )
-    {
-        for( SCH_ITEM* aItem : sheetList[i].LastScreen()->Items().OfType( SCH_MARKER_T ) )
-        {
-            SCH_MARKER* marker = static_cast<SCH_MARKER*>( aItem );
-            int markerSeverity;
-
-            if( marker->GetMarkerType() != MARKER_BASE::MARKER_ERC )
-                continue;
-
-            if( marker->IsExcluded() )
-                markerSeverity = RPT_SEVERITY_EXCLUSION;
-            else
-                markerSeverity = GetSeverity( marker->GetRCItem()->GetErrorCode() );
-
-            if( markerSeverity & m_severities )
-                m_filteredMarkers.push_back( marker );
-        }
-    }
-}
-
-
-int SHEETLIST_ERC_ITEMS_PROVIDER::GetCount( int aSeverity )
-{
-    if( aSeverity < 0 )
-        return m_filteredMarkers.size();
-
-    int count = 0;
-
-    SCH_SHEET_LIST sheetList( g_RootSheet);
-
-    for( unsigned i = 0; i < sheetList.size(); i++ )
-    {
-        for( SCH_ITEM* aItem : sheetList[i].LastScreen()->Items().OfType( SCH_MARKER_T ) )
-        {
-            SCH_MARKER* marker = static_cast<SCH_MARKER*>( aItem );
-            int markerSeverity;
-
-            if( marker->GetMarkerType() != MARKER_BASE::MARKER_ERC )
-                continue;
-
-            if( marker->IsExcluded() )
-                markerSeverity = RPT_SEVERITY_EXCLUSION;
-            else
-                markerSeverity = GetSeverity( marker->GetRCItem()->GetErrorCode() );
-
-            if( markerSeverity == aSeverity )
-                count++;
-        }
-    }
-
-    return count;
-}
-
-
-ERC_ITEM* SHEETLIST_ERC_ITEMS_PROVIDER::GetItem( int aIndex )
-{
-    SCH_MARKER* marker = m_filteredMarkers[ aIndex ];
-
-    return marker ? static_cast<ERC_ITEM*>( marker->GetRCItem() ) : nullptr;
-}
-
-
-void SHEETLIST_ERC_ITEMS_PROVIDER::DeleteItem( int aIndex, bool aDeep )
-{
-    SCH_MARKER* marker = m_filteredMarkers[ aIndex ];
-    m_filteredMarkers.erase( m_filteredMarkers.begin() + aIndex );
-
-    if( aDeep )
-    {
-        SCH_SCREENS ScreenList;
-        ScreenList.DeleteMarker( marker );
-    }
-}
-
-
-void SHEETLIST_ERC_ITEMS_PROVIDER::DeleteAllItems()
-{
-    SCH_SCREENS ScreenList;
-    ScreenList.DeleteAllMarkers( MARKER_BASE::MARKER_ERC );
-    m_filteredMarkers.clear();
-}
diff --git a/eeschema/sch_sheet_path.h b/eeschema/sch_sheet_path.h
index d3df3bbe4a..3cce4ba6e5 100644
--- a/eeschema/sch_sheet_path.h
+++ b/eeschema/sch_sheet_path.h
@@ -270,7 +270,7 @@ public:
      * @param aIncludePowerSymbols : false to only get normal components.
      */
     void GetMultiUnitComponents( SCH_MULTI_UNIT_REFERENCE_MAP &aRefList,
-                                 bool aIncludePowerSymbols = true );
+                                 bool aIncludePowerSymbols = true ) const;
 
     /**
      * Function SetFootprintField
@@ -333,7 +333,6 @@ typedef SCH_SHEET_PATHS::iterator                SCH_SHEET_PATHS_ITER;
 class SCH_SHEET_LIST : public SCH_SHEET_PATHS
 {
 private:
-    bool            m_isRootSheet;
     SCH_SHEET_PATH  m_currentSheetPath;
 
 public:
@@ -360,7 +359,7 @@ public:
     /**
      * Fetch a SCH_ITEM by ID.  Also returns the sheet the item was found on in \a aPathOut.
      */
-    SCH_ITEM* GetItem( const KIID& aID, SCH_SHEET_PATH* aPathOut );
+    SCH_ITEM* GetItem( const KIID& aID, SCH_SHEET_PATH* aPathOut = nullptr );
 
     /**
      * Fill an item cache for temporary use when many items need to be fetched.
@@ -389,7 +388,7 @@ public:
      * The normal option is false, and set to true only to build the full list of components.
      */
     void GetComponents( SCH_REFERENCE_LIST& aReferences, bool aIncludePowerSymbols = true,
-                        bool aForceIncludeOrphanComponents = false );
+                        bool aForceIncludeOrphanComponents = false ) const;
 
     /**
      * Function GetMultiUnitComponents
@@ -401,7 +400,7 @@ public:
      * @param aIncludePowerSymbols Set to false to only get normal components.
      */
     void GetMultiUnitComponents( SCH_MULTI_UNIT_REFERENCE_MAP &aRefList,
-                                 bool aIncludePowerSymbols = true );
+                                 bool aIncludePowerSymbols = true ) const;
 
     /**
      * Function SetFootprintField
@@ -451,7 +450,7 @@ public:
 
     /**
      * Update all of the symbol instance information using \a aSymbolInstances.
-     *
+     * WARNING: Do not call this on anything other than the full hierarchy.
      * @param aSymbolInstances is the symbol path information loaded from the root schematic.
      */
     void UpdateSymbolInstances( std::vector<COMPONENT_INSTANCE_REFERENCE>& aSymbolInstances );
@@ -473,33 +472,4 @@ public:
     void ReplaceLegacySheetPaths( const std::vector<KIID_PATH>& aOldSheetPaths );
 };
 
-
-/**
- * SHEETLIST_ERC_ITEMS_PROVIDER
- * is an implementation of the RC_ITEM_LISTinterface which uses the global SHEETLIST
- * to fulfill the contract.
- */
-class SHEETLIST_ERC_ITEMS_PROVIDER : public RC_ITEMS_PROVIDER
-{
-private:
-    int                      m_severities;
-    std::vector<SCH_MARKER*> m_filteredMarkers;
-
-public:
-    SHEETLIST_ERC_ITEMS_PROVIDER() :
-            m_severities( 0 )
-    { }
-
-    void SetSeverities( int aSeverities ) override;
-
-    int GetCount( int aSeverity = -1 ) override;
-
-    ERC_ITEM* GetItem( int aIndex ) override;
-
-    void DeleteItem( int aIndex, bool aDeep ) override;
-
-    void DeleteAllItems() override;
-};
-
-
 #endif // CLASS_DRAWSHEET_PATH_H
diff --git a/eeschema/sch_text.cpp b/eeschema/sch_text.cpp
index 550a40db20..c2145174f0 100644
--- a/eeschema/sch_text.cpp
+++ b/eeschema/sch_text.cpp
@@ -41,6 +41,7 @@
 #include <math/util.h>      // for KiROUND
 #include <kiway.h>
 #include <sch_text.h>
+#include <schematic.h>
 #include <netlist_object.h>
 #include <settings/color_settings.h>
 #include <sch_painter.h>
@@ -474,7 +475,10 @@ wxString SCH_TEXT::GetShownText( int aDepth ) const
                 {
                     if( token->Contains( ':' ) )
                     {
-                        SCH_SHEET_LIST sheetList( g_RootSheet );
+                        wxCHECK_MSG( Schematic(), wxEmptyString,
+                                     "No parent SCHEMATIC set for SCH_TEXT!" );
+
+                        SCH_SHEET_LIST sheetList = Schematic()->GetSheets();
                         wxString       remainder;
                         wxString       ref = token->BeforeFirst( ':', &remainder );
                         SCH_SHEET_PATH dummy;
@@ -511,10 +515,13 @@ wxString SCH_TEXT::GetShownText( int aDepth ) const
 
     if( processTextVars )
     {
-        PROJECT*  project = nullptr;
+        wxCHECK_MSG( Schematic(), wxEmptyString,
+                     "No parent SCHEMATIC set for SCH_TEXT!" );
 
-        if( g_RootSheet && g_RootSheet->GetScreen() )
-            project = &g_RootSheet->GetScreen()->Kiway().Prj();
+        PROJECT* project = nullptr;
+
+        if( Schematic()->RootScreen() )
+            project = &Schematic()->RootScreen()->Kiway().Prj();
 
         if( aDepth < 10 )
             text = ExpandTextVars( text, &textResolver, project );
@@ -675,8 +682,13 @@ void SCH_TEXT::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, MSG_PANEL_ITEMS& aList )
     aList.push_back( MSG_PANEL_ITEM( _( "Size" ), msg, RED ) );
 
 #if defined(DEBUG)
-    if( auto conn = Connection( *g_CurrentSheet ) )
-        conn->AppendDebugInfoToMsgPanel( aList );
+    SCH_EDIT_FRAME* schframe = dynamic_cast<SCH_EDIT_FRAME*>( aFrame );
+
+    if( schframe )
+    {
+        if( auto conn = Connection( schframe->GetCurrentSheet() ) )
+            conn->AppendDebugInfoToMsgPanel( aList );
+    }
 
     msg.Printf( "%p", this );
     aList.push_back( MSG_PANEL_ITEM( "Object Address", msg, RED ) );
@@ -727,13 +739,17 @@ bool SCH_LABEL::IsType( const KICAD_T aScanTypes[] ) const
     if( SCH_ITEM::IsType( aScanTypes ) )
         return true;
 
+    wxCHECK_MSG( Schematic(), false, "No parent SCHEMATIC set for SCH_LABEL!" );
+
+    SCH_SHEET_PATH current = Schematic()->CurrentSheet();
+
     for( const KICAD_T* p = aScanTypes; *p != EOT; ++p )
     {
         if( *p == SCH_LABEL_LOCATE_WIRE_T )
         {
-            wxASSERT( m_connected_items.count( *g_CurrentSheet ) );
+            wxASSERT( m_connected_items.count( current ) );
 
-            for( SCH_ITEM* connection : m_connected_items.at( *g_CurrentSheet ) )
+            for( SCH_ITEM* connection : m_connected_items.at( current ) )
             {
                 if( connection->IsType( wireTypes ) )
                     return true;
@@ -741,9 +757,9 @@ bool SCH_LABEL::IsType( const KICAD_T aScanTypes[] ) const
         }
         else if ( *p == SCH_LABEL_LOCATE_BUS_T )
         {
-            wxASSERT( m_connected_items.count( *g_CurrentSheet ) );
+            wxASSERT( m_connected_items.count( current ) );
 
-            for( SCH_ITEM* connection : m_connected_items.at( *g_CurrentSheet ) )
+            for( SCH_ITEM* connection : m_connected_items.at( current ) )
             {
                 if( connection->IsType( busTypes ) )
                     return true;
@@ -1097,10 +1113,12 @@ void SCH_HIERLABEL::SetLabelSpinStyle( LABEL_SPIN_STYLE aSpinStyle )
 
 void SCH_HIERLABEL::Print( RENDER_SETTINGS* aSettings, const wxPoint& offset )
 {
+    wxCHECK_RET( Schematic(), "No parent SCHEMATIC set for SCH_LABEL!" );
+
     static std::vector <wxPoint> Poly;
 
     wxDC*           DC = aSettings->GetPrintDC();
-    SCH_CONNECTION* conn = Connection( *g_CurrentSheet );
+    SCH_CONNECTION* conn = Connection( Schematic()->CurrentSheet() );
     bool            isBus = conn && conn->IsBus();
     COLOR4D         color = aSettings->GetLayerColor( isBus ? LAYER_BUS : m_Layer );
     int             penWidth = std::max( GetPenWidth(), aSettings->GetDefaultPenWidth() );
diff --git a/eeschema/schematic.cpp b/eeschema/schematic.cpp
new file mode 100644
index 0000000000..c53cdde068
--- /dev/null
+++ b/eeschema/schematic.cpp
@@ -0,0 +1,203 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2020 KiCad Developers, see AUTHORS.txt for contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <bus_alias.h>
+#include <connection_graph.h>
+#include <erc_settings.h>
+#include <schematic.h>
+#include <sch_screen.h>
+#include <sch_marker.h>
+
+
+SCHEMATIC::SCHEMATIC() :
+          EDA_ITEM( nullptr, SCHEMATIC_T ),
+          m_rootSheet( nullptr )
+{
+    m_currentSheet    = new SCH_SHEET_PATH();
+    m_connectionGraph = new CONNECTION_GRAPH( this );
+    m_ercSettings     = new ERC_SETTINGS();
+}
+
+
+SCHEMATIC::~SCHEMATIC()
+{
+    delete m_currentSheet;
+    delete m_connectionGraph;
+    delete m_ercSettings;
+}
+
+
+void SCHEMATIC::Reset()
+{
+    delete m_rootSheet;
+
+    m_rootSheet = nullptr;
+
+    m_connectionGraph->Reset();
+    m_currentSheet->clear();
+}
+
+
+SCH_SCREEN* SCHEMATIC::RootScreen() const
+{
+    return IsValid() ? m_rootSheet->GetScreen() : nullptr;
+}
+
+
+wxString SCHEMATIC::GetFileName() const
+{
+    return IsValid() ? m_rootSheet->GetScreen()->GetFileName() : wxString( wxEmptyString );
+}
+
+
+std::shared_ptr<BUS_ALIAS> SCHEMATIC::GetBusAlias( const wxString& aLabel ) const
+{
+    for( const auto& sheet : GetSheets() )
+    {
+        for( const auto& alias : sheet.LastScreen()->GetBusAliases() )
+        {
+            if( alias->GetName() == aLabel )
+                return alias;
+        }
+    }
+
+    return nullptr;
+}
+
+
+int SCHEMATIC::GetErcSeverity( int aErrorCode ) const
+{
+    // Special-case pin-to-pin errors:
+    // Ignore-or-not is controlled by ERCE_PIN_TO_PIN_WARNING (for both)
+    // Warning-or-error is controlled by which errorCode it is
+    if( aErrorCode == ERCE_PIN_TO_PIN_ERROR )
+    {
+        if( m_ercSettings->m_Severities[ ERCE_PIN_TO_PIN_WARNING ] == RPT_SEVERITY_IGNORE )
+            return RPT_SEVERITY_IGNORE;
+        else
+            return RPT_SEVERITY_ERROR;
+    }
+    else if( aErrorCode == ERCE_PIN_TO_PIN_WARNING )
+    {
+        if( m_ercSettings->m_Severities[ ERCE_PIN_TO_PIN_WARNING ] == RPT_SEVERITY_IGNORE )
+            return RPT_SEVERITY_IGNORE;
+        else
+            return RPT_SEVERITY_WARNING;
+    }
+
+    return m_ercSettings->m_Severities[ aErrorCode ];
+}
+
+
+void SCHEMATIC::SetErcSeverity( int aErrorCode, int aSeverity )
+{
+    m_ercSettings->m_Severities[ aErrorCode ] = aSeverity;
+}
+
+
+void SHEETLIST_ERC_ITEMS_PROVIDER::SetSeverities( int aSeverities )
+{
+    m_severities = aSeverities;
+
+    m_filteredMarkers.clear();
+
+    SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
+
+    for( unsigned i = 0; i < sheetList.size(); i++ )
+    {
+        for( SCH_ITEM* aItem : sheetList[i].LastScreen()->Items().OfType( SCH_MARKER_T ) )
+        {
+            SCH_MARKER* marker = static_cast<SCH_MARKER*>( aItem );
+            int markerSeverity;
+
+            if( marker->GetMarkerType() != MARKER_BASE::MARKER_ERC )
+                continue;
+
+            if( marker->IsExcluded() )
+                markerSeverity = RPT_SEVERITY_EXCLUSION;
+            else
+                markerSeverity = m_schematic->GetErcSeverity( marker->GetRCItem()->GetErrorCode() );
+
+            if( markerSeverity & m_severities )
+                m_filteredMarkers.push_back( marker );
+        }
+    }
+}
+
+
+int SHEETLIST_ERC_ITEMS_PROVIDER::GetCount( int aSeverity )
+{
+    if( aSeverity < 0 )
+        return m_filteredMarkers.size();
+
+    int count = 0;
+
+    SCH_SHEET_LIST sheetList = m_schematic->GetSheets();
+
+    for( unsigned i = 0; i < sheetList.size(); i++ )
+    {
+        for( SCH_ITEM* aItem : sheetList[i].LastScreen()->Items().OfType( SCH_MARKER_T ) )
+        {
+            SCH_MARKER* marker = static_cast<SCH_MARKER*>( aItem );
+            int markerSeverity;
+
+            if( marker->GetMarkerType() != MARKER_BASE::MARKER_ERC )
+                continue;
+
+            if( marker->IsExcluded() )
+                markerSeverity = RPT_SEVERITY_EXCLUSION;
+            else
+                markerSeverity = m_schematic->GetErcSeverity( marker->GetRCItem()->GetErrorCode() );
+
+            if( markerSeverity == aSeverity )
+                count++;
+        }
+    }
+
+    return count;
+}
+
+
+ERC_ITEM* SHEETLIST_ERC_ITEMS_PROVIDER::GetItem( int aIndex )
+{
+    SCH_MARKER* marker = m_filteredMarkers[ aIndex ];
+
+    return marker ? static_cast<ERC_ITEM*>( marker->GetRCItem() ) : nullptr;
+}
+
+
+void SHEETLIST_ERC_ITEMS_PROVIDER::DeleteItem( int aIndex, bool aDeep )
+{
+    SCH_MARKER* marker = m_filteredMarkers[ aIndex ];
+    m_filteredMarkers.erase( m_filteredMarkers.begin() + aIndex );
+
+    if( aDeep )
+    {
+        SCH_SCREENS screens( m_schematic->Root() );
+        screens.DeleteMarker( marker );
+    }
+}
+
+
+void SHEETLIST_ERC_ITEMS_PROVIDER::DeleteAllItems()
+{
+    SCH_SCREENS screens( m_schematic->Root() );
+    screens.DeleteAllMarkers( MARKER_BASE::MARKER_ERC );
+    m_filteredMarkers.clear();
+}
diff --git a/eeschema/schematic.h b/eeschema/schematic.h
new file mode 100644
index 0000000000..25d24c7036
--- /dev/null
+++ b/eeschema/schematic.h
@@ -0,0 +1,179 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2020 KiCad Developers, see AUTHORS.txt for contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef KICAD_SCHEMATIC_H
+#define KICAD_SCHEMATIC_H
+
+#include <base_struct.h>
+#include <sch_sheet_path.h>
+
+
+class BUS_ALIAS;
+class CONNECTION_GRAPH;
+class EDA_BASE_FRAME;
+class ERC_SETTINGS;
+class SCH_SCREEN;
+class SCH_SHEET;
+
+/**
+ * Holds all the data relating to one schematic
+ * A schematic may consist of one or more sheets (and one root sheet)
+ * Right now, eeschema can have only one schematic open at a time, but this could change.
+ * Please keep this possibility in mind when adding to this object.
+ */
+class SCHEMATIC : public EDA_ITEM
+{
+    friend class SCH_EDIT_FRAME;
+
+private:
+
+    /// The top-level sheet in this schematic hierarchy (or potentially the only one)
+    SCH_SHEET* m_rootSheet;
+
+    /**
+     * The sheet path of the sheet currently being edited or displayed.
+     * Note that this was moved here from SCH_EDIT_FRAME because currently many places in the code
+     * want to know the current sheet.  Potentially this can be moved back to the UI code once
+     * the only places that want to know it are UI-related
+     */
+    SCH_SHEET_PATH* m_currentSheet;
+
+    /// Holds and calculates connectivity information of this schematic
+    CONNECTION_GRAPH* m_connectionGraph;
+
+    /// Holds this schematic's ERC settings
+    // TODO: This should be moved to project settings, not schematic
+    ERC_SETTINGS* m_ercSettings;
+
+public:
+    SCHEMATIC();
+
+    ~SCHEMATIC();
+
+    virtual wxString GetClass() const override
+    {
+        return wxT( "SCHEMATIC" );
+    }
+
+    /// Initializes this schematic to a blank one, unloading anything existing
+    void Reset();
+
+    /**
+     * Builds and returns an updated schematic hierarchy
+     * TODO: can this be cached?
+     * @return a SCH_SHEET_LIST containing the schematic hierarchy
+     */
+    SCH_SHEET_LIST GetSheets() const
+    {
+        return SCH_SHEET_LIST( m_rootSheet );
+    }
+
+    SCH_SHEET& Root() const
+    {
+        return *m_rootSheet;
+    }
+
+    void SetRoot( SCH_SHEET* aRootSheet )
+    {
+        m_rootSheet = aRootSheet;
+    }
+
+    /// A simple test if the schematic is loaded, not a complete one
+    bool IsValid() const
+    {
+        return m_rootSheet != nullptr;
+    }
+
+    /// Helper to retreive the screen of the root sheet
+    SCH_SCREEN* RootScreen() const;
+
+    /// Helper to retrieve the filename from the root sheet screen
+    wxString GetFileName() const;
+
+    SCH_SHEET_PATH& CurrentSheet() const
+    {
+        return *m_currentSheet;
+    }
+
+    void SetCurrentSheet( const SCH_SHEET_PATH& aPath )
+    {
+        *m_currentSheet = aPath;
+    }
+
+    CONNECTION_GRAPH* ConnectionGraph() const
+    {
+        return m_connectionGraph;
+    }
+
+    /**
+     * Returns a pointer to a bus alias object for the given label,
+     * or null if one doesn't exist
+     */
+    std::shared_ptr<BUS_ALIAS> GetBusAlias( const wxString& aLabel ) const;
+
+    ERC_SETTINGS* ErcSettings() const
+    {
+        return m_ercSettings;
+    }
+
+    // TODO(JE) Move out of SCHEMATIC
+    int GetErcSeverity( int aErrorCode ) const;
+
+    // TODO(JE) Move out of SCHEMATIC
+    void SetErcSeverity( int aErrorCode, int aSeverity );
+
+#if defined(DEBUG)
+    void Show( int nestLevel, std::ostream& os ) const override {}
+#endif
+
+};
+
+
+/**
+ * SHEETLIST_ERC_ITEMS_PROVIDER
+ * is an implementation of the RC_ITEM_LISTinterface which uses the global SHEETLIST
+ * to fulfill the contract.
+ */
+class SHEETLIST_ERC_ITEMS_PROVIDER : public RC_ITEMS_PROVIDER
+{
+private:
+    SCHEMATIC*               m_schematic;
+    int                      m_severities;
+    std::vector<SCH_MARKER*> m_filteredMarkers;
+
+public:
+    SHEETLIST_ERC_ITEMS_PROVIDER( SCHEMATIC* aSchematic ) :
+            m_schematic( aSchematic ),
+            m_severities( 0 )
+    { }
+
+    void SetSeverities( int aSeverities ) override;
+
+    int GetCount( int aSeverity = -1 ) override;
+
+    ERC_ITEM* GetItem( int aIndex ) override;
+
+    void DeleteItem( int aIndex, bool aDeep ) override;
+
+    void DeleteAllItems() override;
+};
+
+
+
+#endif
diff --git a/eeschema/sheet.cpp b/eeschema/sheet.cpp
index ce1cfced8e..7aec94736d 100644
--- a/eeschema/sheet.cpp
+++ b/eeschema/sheet.cpp
@@ -36,6 +36,7 @@
 #include <sch_sheet_path.h>
 #include <sch_view.h>
 #include <sch_painter.h>
+#include <schematic.h>
 #include <symbol_lib_table.h>
 #include <dialogs/dialog_sch_sheet_props.h>
 #include <dialogs/dialog_edit_sheet_pin.h>
@@ -47,7 +48,7 @@ bool SCH_EDIT_FRAME::CheckSheetForRecursion( SCH_SHEET* aSheet, SCH_SHEET_PATH*
     wxASSERT( aSheet && aHierarchy );
 
     wxString msg;
-    SCH_SHEET_LIST hierarchy( g_RootSheet );  // This is the full schematic sheet hierarchy.
+    SCH_SHEET_LIST hierarchy = Schematic().GetSheets();  // The full schematic sheet hierarchy.
     SCH_SHEET_LIST sheetHierarchy( aSheet );  // This is the hierarchy of the loaded file.
 
     wxFileName destFile = aHierarchy->LastScreen()->GetFileName();
@@ -113,7 +114,7 @@ bool SCH_EDIT_FRAME::LoadSheetFromFile( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHier
     SCH_SCREEN* currentScreen = aHierarchy->LastScreen();
     SCH_IO_MGR::SCH_FILE_T schFileType = SCH_IO_MGR::GuessPluginTypeFromSchPath( aFileName );
     SCH_PLUGIN::SCH_PLUGIN_RELEASER pi( SCH_IO_MGR::FindPlugin( schFileType ) );
-    std::unique_ptr< SCH_SHEET> newSheet( new SCH_SHEET );
+    std::unique_ptr< SCH_SHEET> newSheet( new SCH_SHEET( &Schematic() ) );
 
     // This will cause the sheet UUID to be set to the loaded schematic UUID.  This is required
     // to ensure all of the sheet paths in any subsheets are correctly generated.
@@ -133,12 +134,12 @@ bool SCH_EDIT_FRAME::LoadSheetFromFile( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHier
     {
         if( aSheet->GetScreen() != nullptr )
         {
-            newSheet.reset( pi->Load( fullFilename, &Kiway() ) );
+            newSheet.reset( pi->Load( fullFilename, &Kiway(), &Schematic() ) );
         }
         else
         {
             newSheet->SetFileName( fullFilename );
-            pi->Load( fullFilename, &Kiway(), newSheet.get() );
+            pi->Load( fullFilename, &Kiway(), &Schematic(), newSheet.get() );
         }
 
         if( !pi->GetError().IsEmpty() )
@@ -209,8 +210,8 @@ bool SCH_EDIT_FRAME::LoadSheetFromFile( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHier
     }
 
     // Make sure any new sheet changes do not cause any recursion issues.
-    SCH_SHEET_LIST hierarchy( g_RootSheet );          // This is the schematic sheet hierarchy.
-    SCH_SHEET_LIST sheetHierarchy( newSheet.get() );  // This is the hierarchy of the loaded file.
+    SCH_SHEET_LIST hierarchy = Schematic().GetSheets(); // This is the schematic sheet hierarchy.
+    SCH_SHEET_LIST sheetHierarchy( newSheet.get() );    // This is the hierarchy of the loaded file.
 
     if( CheckSheetForRecursion( newSheet.get(), aHierarchy )
       || checkForNoFullyDefinedLibIds( newSheet.get() ) )
@@ -221,7 +222,7 @@ bool SCH_EDIT_FRAME::LoadSheetFromFile( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHier
     wxArrayString    names;
     wxArrayString    newLibNames;
     SCH_SCREENS      newScreens( newSheet.get() );   // All screens associated with the import.
-    SCH_SCREENS      prjScreens( g_RootSheet );
+    SCH_SCREENS      prjScreens( &Schematic().Root() );
 
     newScreens.GetLibNicknames( names );
 
@@ -471,7 +472,7 @@ bool SCH_EDIT_FRAME::LoadSheetFromFile( SCH_SHEET* aSheet, SCH_SHEET_PATH* aHier
     else
         aSheet->GetScreen()->Append( newScreen );
 
-    SCH_SCREENS allScreens;
+    SCH_SCREENS allScreens( Schematic().Root() );
     allScreens.ReplaceDuplicateTimeStamps();
 
     return true;
@@ -628,7 +629,7 @@ void SCH_EDIT_FRAME::DrawCurrentSheetToClipboard()
 bool SCH_EDIT_FRAME::AllowCaseSensitiveFileNameClashes( const wxString& aSchematicFileName )
 {
     wxString msg;
-    SCH_SCREENS screens;
+    SCH_SCREENS screens( Schematic().Root() );
     wxFileName fn = aSchematicFileName;
 
     wxCHECK( fn.IsAbsolute(), false );
diff --git a/eeschema/sim/netlist_exporter_pspice_sim.h b/eeschema/sim/netlist_exporter_pspice_sim.h
index 5dc6091de9..e9dd737b5f 100644
--- a/eeschema/sim/netlist_exporter_pspice_sim.h
+++ b/eeschema/sim/netlist_exporter_pspice_sim.h
@@ -46,8 +46,9 @@ struct SPICE_DC_PARAMS
 class NETLIST_EXPORTER_PSPICE_SIM : public NETLIST_EXPORTER_PSPICE
 {
 public:
-    NETLIST_EXPORTER_PSPICE_SIM( NETLIST_OBJECT_LIST* aMasterList, PROJECT* aProject = nullptr ) :
-        NETLIST_EXPORTER_PSPICE( aMasterList, aProject )
+    NETLIST_EXPORTER_PSPICE_SIM( NETLIST_OBJECT_LIST* aMasterList, SCHEMATIC* aSchematic,
+            PROJECT* aProject = nullptr ) :
+            NETLIST_EXPORTER_PSPICE( aMasterList, aSchematic, aProject )
     {
     }
 
diff --git a/eeschema/sim/sim_plot_frame.cpp b/eeschema/sim/sim_plot_frame.cpp
index 46ef02b5b5..d365844136 100644
--- a/eeschema/sim/sim_plot_frame.cpp
+++ b/eeschema/sim/sim_plot_frame.cpp
@@ -672,7 +672,8 @@ void SIM_PLOT_FRAME::removePlot( const wxString& aPlotName, bool aErase )
 
 void SIM_PLOT_FRAME::updateNetlistExporter()
 {
-    m_exporter.reset( new NETLIST_EXPORTER_PSPICE_SIM( m_schematicFrame->BuildNetListBase(), &Prj() ) );
+    m_exporter.reset( new NETLIST_EXPORTER_PSPICE_SIM(
+            m_schematicFrame->BuildNetListBase(), &m_schematicFrame->Schematic(), &Prj() ) );
 }
 
 
diff --git a/eeschema/tools/backanno.cpp b/eeschema/tools/backanno.cpp
index 4d80e44f03..c3807a5ab9 100644
--- a/eeschema/tools/backanno.cpp
+++ b/eeschema/tools/backanno.cpp
@@ -35,6 +35,7 @@
 #include <sch_sheet_path.h>
 #include <sch_component.h>
 #include <sch_reference_list.h>
+#include <schematic.h>
 #include <dsnlexer.h>
 #include <ptree.h>
 #include <boost/property_tree/ptree.hpp>
@@ -46,7 +47,7 @@ void SCH_EDITOR_CONTROL::BackAnnotateFootprints( const std::string& aChangedSetO
 {
     // Build a flat list of components in schematic:
     SCH_REFERENCE_LIST  refs;
-    SCH_SHEET_LIST      sheets( g_RootSheet );
+    SCH_SHEET_LIST      sheets    = m_frame->Schematic().GetSheets();
     bool                isChanged = false;
 
     sheets.GetComponents( refs, false );
@@ -127,7 +128,7 @@ bool SCH_EDITOR_CONTROL::processCmpToFootprintLinkFile( const wxString& aFullFil
 {
     // Build a flat list of components in schematic:
     SCH_REFERENCE_LIST  referencesList;
-    SCH_SHEET_LIST      sheetList( g_RootSheet );
+    SCH_SHEET_LIST      sheetList = m_frame->Schematic().GetSheets();
 
     sheetList.GetComponents( referencesList, false );
 
diff --git a/eeschema/tools/backannotate.cpp b/eeschema/tools/backannotate.cpp
index 7a1479db54..78804fbcc9 100644
--- a/eeschema/tools/backannotate.cpp
+++ b/eeschema/tools/backannotate.cpp
@@ -37,6 +37,7 @@
 #include <reporter.h>
 #include <sch_edit_frame.h>
 #include <sch_sheet_path.h>
+#include <schematic.h>
 #include <utf8.h>
 
 
@@ -68,7 +69,7 @@ bool BACK_ANNOTATE::BackAnnotateSymbols( const std::string& aNetlist )
 
     int errors = getPcbModulesFromString( aNetlist );
 
-    SCH_SHEET_LIST sheets( g_RootSheet );
+    SCH_SHEET_LIST sheets = m_frame->Schematic().GetSheets();
     sheets.GetComponents( m_refs, false );
     sheets.GetMultiUnitComponents( m_multiUnitsRefs );
 
diff --git a/eeschema/tools/ee_selection_tool.cpp b/eeschema/tools/ee_selection_tool.cpp
index 9f14bbd7f8..f27d9ce9ec 100644
--- a/eeschema/tools/ee_selection_tool.cpp
+++ b/eeschema/tools/ee_selection_tool.cpp
@@ -43,6 +43,7 @@
 #include <sch_item.h>
 #include <sch_line.h>
 #include <sch_sheet.h>
+#include <schematic.h>
 #include <tool/tool_event.h>
 #include <tool/tool_manager.h>
 #include <tools/sch_line_wire_bus_tool.h>
@@ -163,12 +164,21 @@ bool EE_SELECTION_TOOL::Init()
     auto schEditCondition = [this] ( const SELECTION& aSel ) {
         return !m_isLibEdit && !m_isLibView;
     };
-    auto belowRootSheetCondition = [this] ( const SELECTION& aSel ) {
-        return !m_isLibEdit && !m_isLibView && g_CurrentSheet->Last() != g_RootSheet;
-    };
-    auto havePartCondition = [ this ] ( const SELECTION& sel ) {
-        return m_isLibEdit && ( (LIB_EDIT_FRAME*) m_frame )->GetCurPart();
-    };
+    auto belowRootSheetCondition =
+            [&]( const SELECTION& aSel )
+            {
+                SCH_EDIT_FRAME* schEditFrame = dynamic_cast<SCH_EDIT_FRAME*>( m_frame );
+
+                return ( schEditFrame&&
+                         schEditFrame->GetCurrentSheet().Last() !=
+                         &schEditFrame->Schematic().Root() );
+            };
+
+    auto havePartCondition =
+            [&]( const SELECTION& sel )
+            {
+                return m_isLibEdit && libEditFrame->GetCurPart();
+            };
 
     auto& menu = m_menu.GetMenu();
 
@@ -315,7 +325,8 @@ int EE_SELECTION_TOOL::Main( const TOOL_EVENT& aEvent )
         // Single click? Select single object
         if( evt->IsClick( BUT_LEFT ) )
         {
-            m_frame->FocusOnItem( nullptr );
+            if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
+                schframe->FocusOnItem( nullptr );
 
             SelectPoint( evt->Position(), EE_COLLECTOR::AllItems, nullptr, false,
                          m_additive, m_subtractive, m_exclusive_or );
@@ -341,7 +352,8 @@ int EE_SELECTION_TOOL::Main( const TOOL_EVENT& aEvent )
         // double click? Display the properties window
         else if( evt->IsDblClick( BUT_LEFT ) )
         {
-            m_frame->FocusOnItem( nullptr );
+            if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
+                schframe->FocusOnItem( nullptr );
 
             if( m_selection.Empty() )
                 SelectPoint( evt->Position());
@@ -357,7 +369,8 @@ int EE_SELECTION_TOOL::Main( const TOOL_EVENT& aEvent )
         // drag with LMB? Select multiple objects (or at least draw a selection box) or drag them
         else if( evt->IsDrag( BUT_LEFT ) )
         {
-            m_frame->FocusOnItem( nullptr );
+            if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
+                schframe->FocusOnItem( nullptr );
 
             if( m_additive || m_subtractive || m_exclusive_or || m_frame->GetDragSelects() )
             {
@@ -412,14 +425,16 @@ int EE_SELECTION_TOOL::Main( const TOOL_EVENT& aEvent )
 
         else if( evt->IsCancelInteractive() )
         {
-            m_frame->FocusOnItem( nullptr );
+            if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
+                schframe->FocusOnItem( nullptr );
 
             ClearSelection();
         }
 
         else if( evt->Action() == TA_UNDO_REDO_PRE )
         {
-            m_frame->FocusOnItem( nullptr );
+            if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
+                schframe->FocusOnItem( nullptr );
 
             ClearSelection();
         }
@@ -1244,14 +1259,18 @@ void EE_SELECTION_TOOL::highlight( EDA_ITEM* aItem, int aMode, EE_SELECTION* aGr
     // represented in the LIB_PART and will inherit the settings of the parent component.)
     if( itemType == SCH_COMPONENT_T )
     {
-        SCH_PIN_PTRS pins = static_cast<SCH_COMPONENT*>( aItem )->GetSchPins( g_CurrentSheet );
-
-        for( SCH_PIN* pin : pins )
+        if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
         {
-            if( aMode == SELECTED )
-                pin->SetSelected();
-            else if( aMode == BRIGHTENED )
-                pin->SetBrightened();
+            SCH_PIN_PTRS pins = static_cast<SCH_COMPONENT*>( aItem )->GetSchPins(
+                    &schframe->GetCurrentSheet() );
+
+            for( SCH_PIN* pin : pins )
+            {
+                if( aMode == SELECTED )
+                    pin->SetSelected();
+                else if( aMode == BRIGHTENED )
+                    pin->SetBrightened();
+            }
         }
 
         for( SCH_FIELD& field : static_cast<SCH_COMPONENT*>( aItem )->GetFields() )
@@ -1304,14 +1323,18 @@ void EE_SELECTION_TOOL::unhighlight( EDA_ITEM* aItem, int aMode, EE_SELECTION* a
     // represented in the LIB_PART.)
     if( itemType == SCH_COMPONENT_T )
     {
-        SCH_PIN_PTRS pins = static_cast<SCH_COMPONENT*>( aItem )->GetSchPins( g_CurrentSheet );
-
-        for( SCH_PIN* pin : pins )
+        if( auto schframe = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
         {
-            if( aMode == SELECTED )
-                pin->ClearSelected();
-            else if( aMode == BRIGHTENED )
-                pin->ClearBrightened();
+            SCH_PIN_PTRS pins = static_cast<SCH_COMPONENT*>( aItem )->GetSchPins(
+                    &schframe->GetCurrentSheet() );
+
+            for( SCH_PIN* pin : pins )
+            {
+                if( aMode == SELECTED )
+                    pin->ClearSelected();
+                else if( aMode == BRIGHTENED )
+                    pin->ClearBrightened();
+            }
         }
 
         for( SCH_FIELD& field : static_cast<SCH_COMPONENT*>( aItem )->GetFields() )
diff --git a/eeschema/tools/lib_control.cpp b/eeschema/tools/lib_control.cpp
index 0a0ca19482..69407fd659 100644
--- a/eeschema/tools/lib_control.cpp
+++ b/eeschema/tools/lib_control.cpp
@@ -442,7 +442,8 @@ int LIB_CONTROL::AddSymbolToSchematic( const TOOL_EVENT& aEvent )
 
         wxCHECK( part->GetLibId().IsValid(), 0 );
 
-        SCH_COMPONENT* comp = new SCH_COMPONENT( *part, libId, g_CurrentSheet, unit, convert );
+        SCH_COMPONENT* comp =
+                new SCH_COMPONENT( *part, libId, &schframe->GetCurrentSheet(), unit, convert );
 
         if( schframe->eeconfig()->m_AutoplaceFields.enable )
             comp->AutoplaceFields( /* aScreen */ nullptr, /* aManual */ false );
diff --git a/eeschema/tools/sch_drawing_tools.cpp b/eeschema/tools/sch_drawing_tools.cpp
index fb03c46a24..54df760162 100644
--- a/eeschema/tools/sch_drawing_tools.cpp
+++ b/eeschema/tools/sch_drawing_tools.cpp
@@ -43,6 +43,7 @@
 #include <sch_text.h>
 #include <sch_sheet.h>
 #include <sch_bitmap.h>
+#include <schematic.h>
 #include <class_library.h>
 #include <eeschema_settings.h>
 
@@ -56,9 +57,11 @@ bool SCH_DRAWING_TOOLS::Init()
 {
     EE_TOOL_BASE::Init();
 
-    auto belowRootSheetCondition = [] ( const SELECTION& aSel ) {
-        return g_CurrentSheet->Last() != g_RootSheet;
-    };
+    auto belowRootSheetCondition =
+            [&]( const SELECTION& aSel )
+            {
+                return m_frame->GetCurrentSheet().Last() != &m_frame->Schematic().Root();
+            };
 
     auto& ctxMenu = m_menu.GetMenu();
     ctxMenu.AddItem( EE_ACTIONS::leaveSheet, belowRootSheetCondition, 2 );
@@ -171,7 +174,8 @@ int SCH_DRAWING_TOOLS::PlaceComponent(  const TOOL_EVENT& aEvent  )
                 if( !part )
                     continue;
 
-                component = new SCH_COMPONENT( *part, g_CurrentSheet, sel, (wxPoint) cursorPos );
+                component = new SCH_COMPONENT(
+                        *part, &m_frame->GetCurrentSheet(), sel, (wxPoint) cursorPos );
                 component->SetFlags( IS_NEW | IS_MOVED );
 
                 if( m_frame->eeconfig()->m_AutoplaceFields.enable )
@@ -218,7 +222,7 @@ int SCH_DRAWING_TOOLS::PlaceComponent(  const TOOL_EVENT& aEvent  )
                         next_comp = static_cast<SCH_COMPONENT*>( component->Duplicate() );
                         next_comp->SetFlags( IS_NEW | IS_MOVED );
                         next_comp->SetUnit( new_unit );
-                        next_comp->SetUnitSelection( g_CurrentSheet, new_unit );
+                        next_comp->SetUnitSelection( &m_frame->GetCurrentSheet(), new_unit );
 
                         if( m_frame->eeconfig()->m_AutoplaceFields.enable )
                             component->AutoplaceFields( /* aScreen */ NULL, /* aManual */ false );
@@ -838,9 +842,9 @@ int SCH_DRAWING_TOOLS::DrawSheet( const TOOL_EVENT& aEvent )
 
             m_toolMgr->RunAction( EE_ACTIONS::clearSelection, true );
 
-            sheet = new SCH_SHEET( (wxPoint) cursorPos );
+            sheet = new SCH_SHEET(
+                    m_frame->GetCurrentSheet().Last(), static_cast<wxPoint>( cursorPos ) );
             sheet->SetFlags( IS_NEW | IS_RESIZED );
-            sheet->SetParent( m_frame->GetCurrentSheet().Last() );
             sheet->SetScreen( NULL );
             sheet->SetBorderWidth( m_frame->GetDefaultLineWidth() );
             sheet->SetBorderColor( cfg->m_Drawing.default_sheet_border_color );
@@ -858,7 +862,8 @@ int SCH_DRAWING_TOOLS::DrawSheet( const TOOL_EVENT& aEvent )
             getViewControls()->SetAutoPan( false );
             getViewControls()->CaptureCursor( false );
 
-            if( m_frame->EditSheetProperties((SCH_SHEET*) sheet, g_CurrentSheet, nullptr ) )
+            if( m_frame->EditSheetProperties(
+                        static_cast<SCH_SHEET*>( sheet ), &m_frame->GetCurrentSheet(), nullptr ) )
             {
                 sheet->AutoplaceFields( /* aScreen */ NULL, /* aManual */ false );
 
diff --git a/eeschema/tools/sch_edit_tool.cpp b/eeschema/tools/sch_edit_tool.cpp
index 661595c559..8e8b57710a 100644
--- a/eeschema/tools/sch_edit_tool.cpp
+++ b/eeschema/tools/sch_edit_tool.cpp
@@ -40,6 +40,7 @@
 #include <sch_line.h>
 #include <sch_bus_entry.h>
 #include <sch_edit_frame.h>
+#include <schematic.h>
 #include <ws_proxy_view_item.h>
 #include <eeschema_id.h>
 #include <status_popup.h>
@@ -770,7 +771,7 @@ int SCH_EDIT_TOOL::Duplicate( const TOOL_EVENT& aEvent )
 
     // Keep track of existing sheet paths. Duplicating a selection can modify this list
     bool copiedSheets = false;
-    SCH_SHEET_LIST initial_sheetpathList( g_RootSheet );
+    SCH_SHEET_LIST initial_sheetpathList = m_frame->Schematic().GetSheets();
 
     for( unsigned ii = 0; ii < selection.GetSize(); ++ii )
     {
@@ -797,12 +798,12 @@ int SCH_EDIT_TOOL::Duplicate( const TOOL_EVENT& aEvent )
 
         case SCH_SHEET_T:
         {
-            SCH_SHEET_LIST hierarchy( g_RootSheet );
-            SCH_SHEET*     sheet = (SCH_SHEET*) newItem;
-            SCH_FIELD&     nameField = sheet->GetFields()[SHEETNAME];
-            wxString       baseName = nameField.GetText();
+            SCH_SHEET_LIST hierarchy     = m_frame->Schematic().GetSheets();
+            SCH_SHEET*     sheet         = (SCH_SHEET*) newItem;
+            SCH_FIELD&     nameField     = sheet->GetFields()[SHEETNAME];
+            wxString       baseName      = nameField.GetText();
             wxString       candidateName = baseName;
-            int            uniquifier = 1;
+            int            uniquifier    = 1;
 
             while( hierarchy.NameExists( candidateName ) )
                 candidateName = wxString::Format( wxT( "%s%d" ), baseName, uniquifier++ );
@@ -834,7 +835,7 @@ int SCH_EDIT_TOOL::Duplicate( const TOOL_EVENT& aEvent )
     {
         // We clear annotation of new sheet paths.
         // Annotation of new components added in current sheet is already cleared.
-        SCH_SCREENS screensList( g_RootSheet );
+        SCH_SCREENS screensList( &m_frame->Schematic().Root() );
         screensList.ClearAnnotationOfNewSheetPaths( initial_sheetpathList );
         m_frame->SetSheetNumberAndCount();
     }
@@ -1113,7 +1114,7 @@ void SCH_EDIT_TOOL::editFieldText( SCH_FIELD* aField )
     if( dlg.ShowQuasiModal() != wxID_OK )
         return;
 
-    dlg.UpdateField( aField, g_CurrentSheet );
+    dlg.UpdateField( aField, &m_frame->GetCurrentSheet() );
 
     if( m_frame->eeconfig()->m_AutoplaceFields.enable || aField->GetParent()->Type() == SCH_SHEET_T )
         static_cast<SCH_ITEM*>( aField->GetParent() )->AutoAutoplaceFields( m_frame->GetScreen() );
@@ -1304,22 +1305,23 @@ int SCH_EDIT_TOOL::Properties( const TOOL_EVENT& aEvent )
         bool           doClearAnnotation;
         bool           doRefresh = false;
         // Keep track of existing sheet paths. EditSheet() can modify this list
-        SCH_SHEET_LIST initial_sheetpathList( g_RootSheet );
+        SCH_SHEET_LIST initial_sheetpathList = m_frame->Schematic().GetSheets();
 
-        doRefresh = m_frame->EditSheetProperties( sheet, g_CurrentSheet, &doClearAnnotation );
+        doRefresh = m_frame->EditSheetProperties(
+                sheet, &m_frame->GetCurrentSheet(), &doClearAnnotation );
 
         // If the sheet file is changed and new sheet contents are loaded then we have to
         // clear the annotations on the new content (as it may have been set from some other
         // sheet path reference)
         if( doClearAnnotation )
         {
-            SCH_SCREENS screensList( g_RootSheet );
+            SCH_SCREENS screensList( &m_frame->Schematic().Root() );
             // We clear annotation of new sheet paths here:
             screensList.ClearAnnotationOfNewSheetPaths( initial_sheetpathList );
             // Clear annotation of g_CurrentSheet itself, because its sheetpath is not a new
             // path, but components managed by its sheet path must have their annotation
             // cleared, because they are new:
-            sheet->GetScreen()->ClearAnnotation( g_CurrentSheet );
+            sheet->GetScreen()->ClearAnnotation( &m_frame->GetCurrentSheet() );
         }
 
         if( doRefresh )
diff --git a/eeschema/tools/sch_editor_control.cpp b/eeschema/tools/sch_editor_control.cpp
index 9f1aa667fb..2054e7cc4f 100644
--- a/eeschema/tools/sch_editor_control.cpp
+++ b/eeschema/tools/sch_editor_control.cpp
@@ -43,6 +43,7 @@
 #include <sch_painter.h>
 #include <sch_sheet.h>
 #include <sch_view.h>
+#include <schematic.h>
 #include <advanced_config.h>
 #include <sim/sim_plot_frame.h>
 #include <simulation_cursors.h>
@@ -115,7 +116,7 @@ int SCH_EDITOR_CONTROL::PageSetup( const TOOL_EVENT& aEvent )
 
 int SCH_EDITOR_CONTROL::RescueSymbols( const TOOL_EVENT& aEvent )
 {
-    SCH_SCREENS schematic;
+    SCH_SCREENS schematic( m_frame->Schematic().Root() );
 
     if( schematic.HasNoFullyDefinedLibIds() )
         RescueLegacyProject( true );
@@ -128,7 +129,7 @@ int SCH_EDITOR_CONTROL::RescueSymbols( const TOOL_EVENT& aEvent )
 
 bool SCH_EDITOR_CONTROL::RescueLegacyProject( bool aRunningOnDemand )
 {
-    LEGACY_RESCUER rescuer( m_frame->Prj(), &m_frame->GetCurrentSheet(),
+    LEGACY_RESCUER rescuer( m_frame->Prj(), &m_frame->Schematic(), &m_frame->GetCurrentSheet(),
                             m_frame->GetCanvas()->GetBackend() );
 
     return rescueProject( rescuer, aRunningOnDemand );
@@ -137,7 +138,8 @@ bool SCH_EDITOR_CONTROL::RescueLegacyProject( bool aRunningOnDemand )
 
 bool SCH_EDITOR_CONTROL::RescueSymbolLibTableProject( bool aRunningOnDemand )
 {
-    SYMBOL_LIB_TABLE_RESCUER rescuer( m_frame->Prj(), &m_frame->GetCurrentSheet(),
+    SYMBOL_LIB_TABLE_RESCUER rescuer( m_frame->Prj(), &m_frame->Schematic(),
+                                      &m_frame->GetCurrentSheet(),
                                       m_frame->GetCanvas()->GetBackend() );
 
     return rescueProject( rescuer, aRunningOnDemand );
@@ -158,10 +160,9 @@ bool SCH_EDITOR_CONTROL::rescueProject( RESCUER& aRescuer, bool aRunningOnDemand
 
         if( aRunningOnDemand )
         {
-            SCH_SCREENS schematic;
+            SCH_SCREENS schematic( m_frame->Schematic().Root() );
 
             schematic.UpdateSymbolLinks();
-            g_ConnectionGraph->Reset();
             m_frame->RecalculateConnections( GLOBAL_CLEANUP );
         }
 
@@ -191,7 +192,7 @@ int SCH_EDITOR_CONTROL::Print( const TOOL_EVENT& aEvent )
 {
     InvokeDialogPrintUsingPrinter( m_frame );
 
-    wxFileName fn = m_frame->Prj().AbsolutePath( g_RootSheet->GetScreen()->GetFileName() );
+    wxFileName fn = m_frame->Prj().AbsolutePath( m_frame->Schematic().RootScreen()->GetFileName() );
 
     if( fn.GetName() != NAMELESS_PROJECT )
         m_frame->SaveProjectSettings();
@@ -409,8 +410,8 @@ int SCH_EDITOR_CONTROL::FindNext( const TOOL_EVENT& aEvent )
 
     if( !item && searchAllSheets )
     {
-        SCH_SHEET_LIST schematic( g_RootSheet );
-        SCH_SCREENS    screens;
+        SCH_SHEET_LIST schematic = m_frame->Schematic().GetSheets();
+        SCH_SCREENS    screens( m_frame->Schematic().Root() );
 
         for( SCH_SCREEN* screen = screens.GetFirst(); screen; screen = screens.GetNext() )
         {
@@ -429,8 +430,8 @@ int SCH_EDITOR_CONTROL::FindNext( const TOOL_EVENT& aEvent )
                 SCH_SHEET_PATH* sheet = schematic.FindSheetForScreen( screen );
                 wxCHECK_MSG( sheet, 0, "Sheet not found for " + screen->GetFileName() );
 
-                *g_CurrentSheet = *sheet;
-                g_CurrentSheet->UpdateAllScreenReferences();
+                m_frame->Schematic().SetCurrentSheet( *sheet );
+                m_frame->GetCurrentSheet().UpdateAllScreenReferences();
 
                 screen->SetZoom( m_frame->GetScreen()->GetZoom() );
                 screen->TestDanglingEnds();
@@ -481,7 +482,7 @@ int SCH_EDITOR_CONTROL::ReplaceAndFindNext( const TOOL_EVENT& aEvent )
 
     if( item && item->Matches( *data, nullptr ) )
     {
-        if( item->Replace( *data, g_CurrentSheet ) )
+        if( item->Replace( *data, &m_frame->GetCurrentSheet() ) )
         {
             m_frame->RefreshItem( item );
             m_frame->OnModify();
@@ -501,8 +502,8 @@ int SCH_EDITOR_CONTROL::ReplaceAll( const TOOL_EVENT& aEvent )
     if( !data )
         return FindAndReplace( ACTIONS::find.MakeEvent() );
 
-    SCH_SHEET_LIST schematic( g_RootSheet );
-    SCH_SCREENS    screens;
+    SCH_SHEET_LIST schematic = m_frame->Schematic().GetSheets();
+    SCH_SCREENS    screens( m_frame->Schematic().Root() );
 
     for( SCH_SCREEN* screen = screens.GetFirst(); screen; screen = screens.GetNext() )
     {
@@ -663,7 +664,7 @@ int SCH_EDITOR_CONTROL::SimProbe( const TOOL_EVENT& aEvent )
                 else
                     param = wxString::Format( wxT( "I%s" ), pin->GetName().Lower() );
 
-                simFrame->AddCurrentPlot( comp->GetRef( g_CurrentSheet ), param );
+                simFrame->AddCurrentPlot( comp->GetRef( &m_frame->GetCurrentSheet() ), param );
             }
 
             return true;
@@ -687,8 +688,8 @@ int SCH_EDITOR_CONTROL::SimProbe( const TOOL_EVENT& aEvent )
             {
                 item = nullptr;
 
-                if( wire->Connection( *g_CurrentSheet ) )
-                    netName = wire->Connection( *g_CurrentSheet )->Name();
+                if( wire->Connection( m_frame->GetCurrentSheet() ) )
+                    netName = wire->Connection( m_frame->GetCurrentSheet() )->Name();
             }
 
             if( item && item->Type() == SCH_PIN_T )
@@ -828,7 +829,7 @@ static bool highlightNet( TOOL_MANAGER* aToolMgr, const VECTOR2D& aPosition )
 
     if( aPosition != CLEAR )
     {
-        if( TestDuplicateSheetNames( false ) > 0 )
+        if( TestDuplicateSheetNames( &editFrame->Schematic(), false ) > 0 )
         {
             wxMessageBox( _( "Error: duplicate sub-sheet names found in current sheet." ) );
             retVal = false;
@@ -848,8 +849,8 @@ static bool highlightNet( TOOL_MANAGER* aToolMgr, const VECTOR2D& aPosition )
 
             if( comp && comp->GetPartRef() && comp->GetPartRef()->IsPower() )
                 netName = comp->GetPartRef()->GetName();
-            else if( item && item->Connection( *g_CurrentSheet ) )
-                netName = item->Connection( *g_CurrentSheet )->Name();
+            else if( item && item->Connection( editFrame->GetCurrentSheet() ) )
+                netName = item->Connection( editFrame->GetCurrentSheet() )->Name();
         }
     }
 
@@ -894,7 +895,7 @@ int SCH_EDITOR_CONTROL::ClearHighlight( const TOOL_EVENT& aEvent )
 
 int SCH_EDITOR_CONTROL::UpdateNetHighlighting( const TOOL_EVENT& aEvent )
 {
-    SCH_SCREEN*            screen = g_CurrentSheet->LastScreen();
+    SCH_SCREEN*            screen = m_frame->GetCurrentSheet().LastScreen();
     std::vector<EDA_ITEM*> itemsToRedraw;
     wxString               selectedNetName = m_frame->GetSelectedNetName();
 
@@ -916,7 +917,7 @@ int SCH_EDITOR_CONTROL::UpdateNetHighlighting( const TOOL_EVENT& aEvent )
         }
         else
         {
-            SCH_CONNECTION* connection = item->Connection( *g_CurrentSheet );
+            SCH_CONNECTION* connection = item->Connection( m_frame->GetCurrentSheet() );
 
             if( connection )
                 itemConnectionName = connection->Name();
@@ -939,7 +940,8 @@ int SCH_EDITOR_CONTROL::UpdateNetHighlighting( const TOOL_EVENT& aEvent )
 
             for( LIB_PIN* pin : pins )
             {
-                SCH_CONNECTION* pin_conn = comp->GetConnectionForPin( pin, *g_CurrentSheet );
+                SCH_CONNECTION* pin_conn =
+                        comp->GetConnectionForPin( pin, m_frame->GetCurrentSheet() );
 
                 if( comp && pin_conn && pin_conn->Name( false ) == selectedNetName )
                 {
@@ -965,7 +967,7 @@ int SCH_EDITOR_CONTROL::UpdateNetHighlighting( const TOOL_EVENT& aEvent )
         {
             for( SCH_SHEET_PIN* pin : static_cast<SCH_SHEET*>( item )->GetPins() )
             {
-                SCH_CONNECTION* pin_conn = pin->Connection( *g_CurrentSheet );
+                SCH_CONNECTION* pin_conn = pin->Connection( m_frame->GetCurrentSheet() );
                 bool            redrawPin = pin->IsBrightened();
 
                 if( pin_conn && pin_conn->Name() == selectedNetName )
@@ -1214,10 +1216,11 @@ int SCH_EDITOR_CONTROL::Paste( const TOOL_EVENT& aEvent )
     // SCH_SEXP_PLUGIN added the items to the paste screen, but not to the view or anything
     // else.  Pull them back out to start with.
     //
-    EDA_ITEMS      loadedItems;
-    bool           sheetsPasted = false;
-    SCH_SHEET_LIST hierarchy( g_RootSheet );
-    wxFileName     destFn = g_CurrentSheet->Last()->GetFileName();
+    EDA_ITEMS       loadedItems;
+    bool            sheetsPasted = false;
+    SCH_SHEET_LIST  hierarchy    = m_frame->Schematic().GetSheets();
+    SCH_SHEET_PATH& currentSheet = m_frame->GetCurrentSheet();
+    wxFileName      destFn       = currentSheet.Last()->GetFileName();
 
     if( destFn.IsRelative() )
         destFn.MakeAbsolute( m_frame->Prj().GetProjectPath() );
@@ -1304,31 +1307,32 @@ int SCH_EDITOR_CONTROL::Paste( const TOOL_EVENT& aEvent )
 
         if( item->Type() == SCH_SHEET_T )
         {
-            SCH_SHEET*  sheet = (SCH_SHEET*) item;
-            SCH_FIELD&  nameField = sheet->GetFields()[SHEETNAME];
-            wxFileName  fn = sheet->GetFileName();
-            SCH_SCREEN* existingScreen = nullptr;
-            bool        dropSheetAnnotations = false;
-            wxString    baseName = nameField.GetText();
-            wxString    candidateName = baseName;
-            int         uniquifier = 1;
+            SCH_SHEET*      sheet                = (SCH_SHEET*) item;
+            SCH_FIELD&      nameField            = sheet->GetFields()[SHEETNAME];
+            wxFileName      fn                   = sheet->GetFileName();
+            SCH_SCREEN*     existingScreen       = nullptr;
+            bool            dropSheetAnnotations = false;
+            wxString        baseName             = nameField.GetText();
+            wxString        candidateName        = baseName;
+            int             uniquifier           = 1;
 
             while( hierarchy.NameExists( candidateName ) )
                 candidateName = wxString::Format( wxT( "%s%d" ), baseName, uniquifier++ );
 
             nameField.SetText( candidateName );
 
-            sheet->SetParent( g_CurrentSheet->Last() );
+            sheet->SetParent( currentSheet.Last() );
             sheet->SetScreen( nullptr );
             sheetsPasted = true;
 
             if( !fn.IsAbsolute() )
             {
-                wxFileName currentSheetFileName = g_CurrentSheet->LastScreen()->GetFileName();
+                wxFileName currentSheetFileName = currentSheet.LastScreen()->GetFileName();
                 fn.Normalize( wxPATH_NORM_ALL, currentSheetFileName.GetPath() );
             }
 
-            if( g_RootSheet->SearchHierarchy( fn.GetFullPath( wxPATH_UNIX ), &existingScreen ) )
+            if( m_frame->Schematic().Root().SearchHierarchy(
+                        fn.GetFullPath( wxPATH_UNIX ), &existingScreen ) )
                 dropSheetAnnotations = !forceKeepAnnotations;
             else
                 searchSupplementaryClipboard( sheet->GetFileName(), &existingScreen );
@@ -1337,7 +1341,7 @@ int SCH_EDITOR_CONTROL::Paste( const TOOL_EVENT& aEvent )
             {
                 sheet->SetScreen( existingScreen );
 
-                SCH_SHEET_PATH sheetpath = *g_CurrentSheet;
+                SCH_SHEET_PATH sheetpath = currentSheet;
                 sheetpath.push_back( sheet );
 
                 // Clear annotation and create the AR for this path, if not exists,
@@ -1351,7 +1355,7 @@ int SCH_EDITOR_CONTROL::Paste( const TOOL_EVENT& aEvent )
             }
             else
             {
-                if( !m_frame->LoadSheetFromFile( sheet, g_CurrentSheet, fn.GetFullPath() ) )
+                if( !m_frame->LoadSheetFromFile( sheet, &currentSheet, fn.GetFullPath() ) )
                     m_frame->InitSheet( sheet, sheet->GetFileName() );
             }
         }
@@ -1517,7 +1521,7 @@ int SCH_EDITOR_CONTROL::EnterSheet( const TOOL_EVENT& aEvent )
         m_toolMgr->RunAction( ACTIONS::cancelInteractive, true );
         m_toolMgr->RunAction( EE_ACTIONS::clearSelection, true );
 
-        g_CurrentSheet->push_back( sheet );
+        m_frame->GetCurrentSheet().push_back( sheet );
         m_frame->DisplayCurrentSheet();
         m_frame->UpdateHierarchyNavigator();
     }
@@ -1528,12 +1532,12 @@ int SCH_EDITOR_CONTROL::EnterSheet( const TOOL_EVENT& aEvent )
 
 int SCH_EDITOR_CONTROL::LeaveSheet( const TOOL_EVENT& aEvent )
 {
-    if( g_CurrentSheet->Last() != g_RootSheet )
+    if( m_frame->GetCurrentSheet().Last() != &m_frame->Schematic().Root() )
     {
         m_toolMgr->RunAction( ACTIONS::cancelInteractive, true );
         m_toolMgr->RunAction( EE_ACTIONS::clearSelection, true );
 
-        g_CurrentSheet->pop_back();
+        m_frame->GetCurrentSheet().pop_back();
         m_frame->DisplayCurrentSheet();
         m_frame->UpdateHierarchyNavigator();
     }
diff --git a/eeschema/tools/sch_line_wire_bus_tool.cpp b/eeschema/tools/sch_line_wire_bus_tool.cpp
index ef0ced3eb1..593876db2d 100644
--- a/eeschema/tools/sch_line_wire_bus_tool.cpp
+++ b/eeschema/tools/sch_line_wire_bus_tool.cpp
@@ -74,6 +74,7 @@
 #include <sch_sheet_path.h>
 #include <sch_text.h>
 #include <sch_view.h>
+#include <schematic.h>
 
 #include <ee_actions.h>
 #include <ee_point_editor.h>
@@ -131,7 +132,7 @@ private:
             return;
         }
 
-        SCH_CONNECTION* connection = bus->Connection( *g_CurrentSheet );
+        SCH_CONNECTION* connection = bus->Connection( frame->GetCurrentSheet() );
 
         if( !connection ||  !connection->IsBus() || connection->Members().empty() )
         {
@@ -203,9 +204,11 @@ bool SCH_LINE_WIRE_BUS_TOOL::Init()
         return ( m_frame->IsCurrentTool( EE_ACTIONS::drawLines ) );
     };
 
-    auto belowRootSheetCondition = [] ( const SELECTION& aSel ) {
-        return g_CurrentSheet->Last() != g_RootSheet;
-    };
+    auto belowRootSheetCondition =
+            [&]( const SELECTION& aSel )
+            {
+                return m_frame->GetCurrentSheet().Last() != &m_frame->Schematic().Root();
+            };
 
     auto busSelection = EE_CONDITIONS::MoreThan( 0 )
                             && EE_CONDITIONS::OnlyType( SCH_LINE_LOCATE_BUS_T );
diff --git a/include/core/typeinfo.h b/include/core/typeinfo.h
index 4d73369814..92136adaba 100644
--- a/include/core/typeinfo.h
+++ b/include/core/typeinfo.h
@@ -159,6 +159,8 @@ enum KICAD_T
     // General
     SCH_SCREEN_T,
 
+    SCHEMATIC_T,
+
     /*
      * Draw items in library component.
      *
diff --git a/qa/eeschema/sim/test_netlist_exporter_pspice_sim.cpp b/qa/eeschema/sim/test_netlist_exporter_pspice_sim.cpp
index 1b3d46eca4..4473cb0b13 100644
--- a/qa/eeschema/sim/test_netlist_exporter_pspice_sim.cpp
+++ b/qa/eeschema/sim/test_netlist_exporter_pspice_sim.cpp
@@ -39,7 +39,8 @@ class TEST_NETLIST_EXPORTER_PSPICE_SIM
 {
 public:
     TEST_NETLIST_EXPORTER_PSPICE_SIM()
-            : m_netlist( new NETLIST_OBJECT_LIST ), m_exporter( m_netlist )
+            : m_netlist( new NETLIST_OBJECT_LIST ),
+              m_exporter( m_netlist, nullptr )
     {
     }
 
diff --git a/qa/eeschema/test_sch_sheet.cpp b/qa/eeschema/test_sch_sheet.cpp
index b6fadcd497..8c5bd7bde0 100644
--- a/qa/eeschema/test_sch_sheet.cpp
+++ b/qa/eeschema/test_sch_sheet.cpp
@@ -30,6 +30,7 @@
 
 // Code under test
 #include <sch_sheet.h>
+#include <schematic.h>
 
 #include "uuid_test_utils.h"
 
@@ -42,6 +43,9 @@ public:
     {
     }
 
+    ///> Dummy schematic to attach the test sheet to
+    SCHEMATIC m_schematic;
+
     SCH_SHEET m_sheet;
 
     ///> Can use when you need a const ref (lots of places need fixing here)
@@ -73,8 +77,7 @@ BOOST_AUTO_TEST_CASE( Default )
 {
     BOOST_CHECK_EQUAL( m_csheet.GetPosition(), wxPoint( 0, 0 ) );
 
-    // it is it's own root sheet
-    BOOST_CHECK_EQUAL( m_sheet.GetRootSheet(), &m_sheet );
+    BOOST_CHECK_EQUAL( m_sheet.GetParent(), nullptr );
     BOOST_CHECK_EQUAL( m_sheet.CountSheets(), 1 );
 
     BOOST_CHECK_EQUAL( m_csheet.GetScreenCount(), 0 );
@@ -82,6 +85,20 @@ BOOST_AUTO_TEST_CASE( Default )
     BOOST_CHECK_EQUAL( m_sheet.ComponentCount(), 0 );
 }
 
+/**
+ * Test setting parent schematic
+ */
+BOOST_AUTO_TEST_CASE( SchematicParent )
+{
+    m_sheet.SetParent( &m_schematic );
+
+    BOOST_CHECK_EQUAL( m_sheet.IsRootSheet(), false );
+
+    m_schematic.SetRoot( &m_sheet );
+
+    BOOST_CHECK_EQUAL( m_sheet.IsRootSheet(), true );
+}
+
 /**
  * Test adding pins to a sheet
  */
diff --git a/qa/eeschema/test_sch_sheet_path.cpp b/qa/eeschema/test_sch_sheet_path.cpp
index dbfd8ac6b4..006e1ee566 100644
--- a/qa/eeschema/test_sch_sheet_path.cpp
+++ b/qa/eeschema/test_sch_sheet_path.cpp
@@ -44,7 +44,7 @@ public:
     {
         for( unsigned i = 0; i < 4; ++i )
         {
-            m_sheets.emplace_back( wxPoint( i, i ) );
+            m_sheets.emplace_back( nullptr, wxPoint( i, i ) );
 
             std::ostringstream ss;
             ss << "Sheet" << i;