diff --git a/common/gal/opengl/opengl_compositor.cpp b/common/gal/opengl/opengl_compositor.cpp
index 9ed87f29c1..8610ca4a4a 100644
--- a/common/gal/opengl/opengl_compositor.cpp
+++ b/common/gal/opengl/opengl_compositor.cpp
@@ -39,6 +39,7 @@
 #include <memory>
 #include <stdexcept>
 #include <wx/log.h>
+#include <wx/debug.h>
 
 using namespace KIGFX;
 
@@ -171,10 +172,9 @@ unsigned int OPENGL_COMPOSITOR::CreateBuffer( VECTOR2U aDimensions )
 
     if( (int) usedBuffers() >= maxBuffers )
     {
-        throw std::runtime_error(
-                "Cannot create more framebuffers. OpenGL rendering "
-                "backend requires at least 3 framebuffers. You may try to update/change "
-                "your graphic drivers." );
+        throw std::runtime_error( "Cannot create more framebuffers. OpenGL rendering backend "
+                                  "requires at least 3 framebuffers. You may try to update/change "
+                                  "your graphic drivers." );
     }
 
     glGetIntegerv( GL_MAX_TEXTURE_SIZE, (GLint*) &maxTextureSize );
@@ -218,46 +218,35 @@ unsigned int OPENGL_COMPOSITOR::CreateBuffer( VECTOR2U aDimensions )
         {
         case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
             throw std::runtime_error( "The framebuffer attachment points are incomplete." );
-            break;
 
         case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
             throw std::runtime_error( "No images attached to the framebuffer." );
-            break;
 
         case GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
             throw std::runtime_error( "The framebuffer does not have at least one "
                                       "image attached to it." );
-            break;
 
         case GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
             throw std::runtime_error( "The framebuffer read buffer is incomplete." );
-            break;
 
         case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
-            throw std::runtime_error(
-                    "The combination of internal formats of the attached "
-                    "images violates an implementation-dependent set of restrictions." );
-            break;
+            throw std::runtime_error( "The combination of internal formats of the attached "
+                                      "images violates an implementation-dependent set of "
+                                      "restrictions." );
 
         case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT:
             throw std::runtime_error( "GL_RENDERBUFFER_SAMPLES is not the same for "
                                       "all attached renderbuffers" );
-            break;
 
         case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS_EXT:
             throw std::runtime_error( "Framebuffer incomplete layer targets errors." );
-            break;
 
         case GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
             throw std::runtime_error( "Framebuffer attachments have different dimensions" );
-            break;
 
         default:
             throw std::runtime_error( "Unknown error occurred when creating the framebuffer." );
-            break;
         }
-
-        return 0;
     }
 
     ClearBuffer( COLOR4D::BLACK );
@@ -275,15 +264,15 @@ unsigned int OPENGL_COMPOSITOR::CreateBuffer( VECTOR2U aDimensions )
 
 GLenum OPENGL_COMPOSITOR::GetBufferTexture( unsigned int aBufferHandle )
 {
-    assert( aBufferHandle > 0 && aBufferHandle <= usedBuffers() );
+    wxASSERT( aBufferHandle > 0 && aBufferHandle <= usedBuffers() );
     return m_buffers[aBufferHandle - 1].textureTarget;
 }
 
 
 void OPENGL_COMPOSITOR::SetBuffer( unsigned int aBufferHandle )
 {
-    assert( m_initialized );
-    assert( aBufferHandle <= usedBuffers() );
+    wxASSERT( m_initialized );
+    wxASSERT( aBufferHandle <= usedBuffers() );
 
     // Either unbind the FBO for direct rendering, or bind the one with target textures
     bindFb( aBufferHandle == DIRECT_RENDERING ? DIRECT_RENDERING : m_mainFbo );
@@ -307,7 +296,7 @@ void OPENGL_COMPOSITOR::SetBuffer( unsigned int aBufferHandle )
 
 void OPENGL_COMPOSITOR::ClearBuffer( const COLOR4D& aColor )
 {
-    assert( m_initialized );
+    wxASSERT( m_initialized );
 
     glClearColor( aColor.r, aColor.g, aColor.b, 0.0f );
     glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT );
@@ -334,9 +323,9 @@ void OPENGL_COMPOSITOR::DrawBuffer( unsigned int aBufferHandle )
 
 void OPENGL_COMPOSITOR::DrawBuffer( unsigned int aSourceHandle, unsigned int aDestHandle )
 {
-    assert( m_initialized );
-    assert( aSourceHandle != 0 && aSourceHandle <= usedBuffers() );
-    assert( aDestHandle <= usedBuffers() );
+    wxASSERT( m_initialized );
+    wxASSERT( aSourceHandle != 0 && aSourceHandle <= usedBuffers() );
+    wxASSERT( aDestHandle <= usedBuffers() );
 
     // Switch to the destination buffer and blit the scene
     SetBuffer( aDestHandle );
@@ -388,7 +377,7 @@ void OPENGL_COMPOSITOR::Present()
 void OPENGL_COMPOSITOR::bindFb( unsigned int aFb )
 {
     // Currently there are only 2 valid FBOs
-    assert( aFb == DIRECT_RENDERING || aFb == m_mainFbo );
+    wxASSERT( aFb == DIRECT_RENDERING || aFb == m_mainFbo );
 
     if( m_curFbo != aFb )
     {
@@ -401,14 +390,12 @@ void OPENGL_COMPOSITOR::bindFb( unsigned int aFb )
 
 void OPENGL_COMPOSITOR::clean()
 {
-    assert( m_initialized );
+    wxASSERT( m_initialized );
 
     bindFb( DIRECT_RENDERING );
 
-    for( OPENGL_BUFFERS::const_iterator it = m_buffers.begin(); it != m_buffers.end(); ++it )
-    {
-        glDeleteTextures( 1, &it->textureTarget );
-    }
+    for( const OPENGL_BUFFER& buffer : m_buffers )
+        glDeleteTextures( 1, &buffer.textureTarget );
 
     m_buffers.clear();
 
@@ -426,10 +413,8 @@ int OPENGL_COMPOSITOR::GetAntialiasSupersamplingFactor() const
 {
     switch ( m_currentAntialiasingMode )
     {
-    case OPENGL_ANTIALIASING_MODE::SUPERSAMPLING:
-        return 2;
-    default:
-        return 1;
+    case OPENGL_ANTIALIASING_MODE::SUPERSAMPLING: return 2;
+    default:                                      return 1;
     }
 }
 
@@ -438,6 +423,6 @@ VECTOR2D OPENGL_COMPOSITOR::GetAntialiasRenderingOffset() const
     switch( m_currentAntialiasingMode )
     {
     case OPENGL_ANTIALIASING_MODE::SUPERSAMPLING: return VECTOR2D( 0.5, -0.5 );
-    default: return VECTOR2D( 0, 0 );
+    default:                                      return VECTOR2D( 0, 0 );
     }
 }
diff --git a/common/gal/opengl/utils.cpp b/common/gal/opengl/utils.cpp
index af60c7a3ca..e91d9d87e8 100644
--- a/common/gal/opengl/utils.cpp
+++ b/common/gal/opengl/utils.cpp
@@ -90,13 +90,13 @@ int checkGlError( const std::string& aInfo, const char* aFile, int aLine, bool a
                 break;
 
             case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
-                errorMsg = "The combination of internal formats of the attached images violates an "
-                           "implementation dependent set of restrictions.";
+                errorMsg = "The combination of internal formats of the attached images violates "
+                           "an implementation dependent set of restrictions.";
                 break;
 
             case GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE_EXT:
-                errorMsg =
-                        "GL_RENDERBUFFER_SAMPLES is not the same for all attached render buffers.";
+                errorMsg = "GL_RENDERBUFFER_SAMPLES is not the same for all attached render "
+                           "buffers.";
                 break;
 
             case GL_FRAMEBUFFER_INCOMPLETE_LAYER_TARGETS_EXT:
@@ -140,16 +140,20 @@ int checkGlError( const std::string& aInfo, const char* aFile, int aLine, bool a
         if( aThrow )
         {
             wxLogTrace( traceGalOpenGlError, wxT( "Throwing exception for glGetError() '%s' "
-                                                  "in file '%s' on line %d." ), errorMsg,
-                        aFile, aLine );
+                                                  "in file '%s' on line %d." ),
+                        errorMsg,
+                        aFile,
+                        aLine );
+
             throw std::runtime_error( (const char*) errorMsg.char_str() );
         }
         else
         {
-            wxString msg;
+            wxString msg = wxString::Format( wxT( "glGetError() '%s' in file '%s' on line %d." ),
+                                             errorMsg,
+                                             aFile,
+                                             aLine );
 
-            msg.Printf( wxT( "glGetError() '%s' in file '%s' on line %d." ),
-                        errorMsg, aFile, aLine );
             DisplayErrorMessage( nullptr, "OpenGL Error", errorMsg );
         }
     }
diff --git a/common/tool/edit_points.cpp b/common/tool/edit_points.cpp
index a1b8889f2f..92f0a49a3c 100644
--- a/common/tool/edit_points.cpp
+++ b/common/tool/edit_points.cpp
@@ -53,14 +53,14 @@ EDIT_POINT* EDIT_POINTS::FindPoint( const VECTOR2I& aLocation, KIGFX::VIEW *aVie
 
     if( m_allowPoints )
     {
-        for( auto& point : m_points )
+        for( EDIT_POINT& point : m_points )
         {
             if( point.WithinPoint( aLocation, size ) )
                 return &point;
         }
     }
 
-    for( auto& line : m_lines )
+    for( EDIT_LINE& line : m_lines )
     {
         if( line.WithinPoint( aLocation, size ) )
             return &line;
@@ -244,8 +244,7 @@ const BOX2I EDIT_POINTS::ViewBBox() const
 
 void EDIT_POINTS::ViewDraw( int aLayer, KIGFX::VIEW* aView ) const
 {
-    auto gal = aView->GetGAL();
-
+    KIGFX::GAL*             gal = aView->GetGAL();
     KIGFX::RENDER_SETTINGS* settings = aView->GetPainter()->GetSettings();
     KIGFX::COLOR4D          drawColor = settings->GetLayerColor( LAYER_AUX_ITEMS );
 
diff --git a/common/tool/selection.cpp b/common/tool/selection.cpp
index 1a99f015cc..e66375f8ed 100644
--- a/common/tool/selection.cpp
+++ b/common/tool/selection.cpp
@@ -2,6 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2013-2017 CERN
+ * Copyright (C) 2021 KiCad Developers, see AUTHORS.txt for contributors.
  * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
  * @author Maciej Suminski <maciej.suminski@cern.ch>
  *
@@ -119,7 +120,7 @@ bool SELECTION::HasType( KICAD_T aType ) const
 }
 
 
-const KIGFX::VIEW_GROUP::ITEMS SELECTION::updateDrawList() const
+const std::vector<KIGFX::VIEW_ITEM*> SELECTION::updateDrawList() const
 {
     std::vector<VIEW_ITEM*> items;
 
diff --git a/common/view/view.cpp b/common/view/view.cpp
index ac9b4d371d..a127e5016e 100644
--- a/common/view/view.cpp
+++ b/common/view/view.cpp
@@ -64,7 +64,7 @@ public:
         deleteGroups();
     }
 
-    int getFlags() const
+    int GetFlags() const
     {
         return m_flags;
     }
@@ -124,7 +124,7 @@ private:
         }
 
         // If there was no entry for the given layer - create one
-        GroupPair* newGroups = new GroupPair[m_groupsSize + 1];
+        std::pair<int, int>* newGroups = new std::pair<int, int>[m_groupsSize + 1];
 
         if( m_groupsSize > 0 )
         {
@@ -133,7 +133,7 @@ private:
         }
 
         m_groups = newGroups;
-        newGroups[m_groupsSize++] = GroupPair( aLayer, aGroup );
+        newGroups[m_groupsSize++] = { aLayer, aGroup };
     }
 
 
@@ -177,7 +177,8 @@ private:
             {
                 new_layer = aReorderMap.at( orig_layer );
             }
-            catch( const std::out_of_range& ) {}
+            catch( const std::out_of_range& )
+            {}
 
             m_groups[i].first = new_layer;
         }
@@ -226,22 +227,16 @@ private:
         return m_flags == VISIBLE;
     }
 
+    VIEW*                m_view;             ///< Current dynamic view the item is assigned to.
+    int                  m_flags;            ///< Visibility flags
+    int                  m_requiredUpdate;   ///< Flag required for updating
+    int                  m_drawPriority;     ///< Order to draw this item in a layer, lowest first
 
-    VIEW*   m_view;             ///< Current dynamic view the item is assigned to.
-    int     m_flags;            ///< Visibility flags
-    int     m_requiredUpdate;   ///< Flag required for updating
-    int     m_drawPriority;     ///< Order to draw this item in a layer, lowest first
+    std::pair<int, int>* m_groups;           ///< layer_number:group_id pairs for each layer the
+                                             ///< item occupies.
+    int                  m_groupsSize;
 
-    ///< Helper for storing cached items group ids
-    typedef std::pair<int, int> GroupPair;
-
-    ///< Indexes of cached GAL display lists corresponding to the item (for every layer it.
-    ///<  occupies)(in the std::pair "first" stores layer number, "second" stores group id).
-    GroupPair* m_groups;
-    int        m_groupsSize;
-
-    /// Stores layer numbers used by the item.
-    std::vector<int> m_layers;
+    std::vector<int>     m_layers;           /// Stores layer numbers used by the item.
 };
 
 
@@ -415,7 +410,7 @@ struct QUERY_VISITOR
 
     bool operator()( VIEW_ITEM* aItem )
     {
-        if( aItem->viewPrivData()->getFlags() & VISIBLE )
+        if( aItem->viewPrivData()->GetFlags() & VISIBLE )
             m_cont.push_back( VIEW::LAYER_ITEM_PAIR( aItem, m_layer ) );
 
         return true;
@@ -733,7 +728,7 @@ struct VIEW::UPDATE_COLOR_VISITOR
     {
         // Obtain the color that should be used for coloring the item
         const COLOR4D color = painter->GetSettings()->GetColor( aItem, layer );
-        int group = aItem->viewPrivData()->getGroup( layer );
+        int           group = aItem->viewPrivData()->getGroup( layer );
 
         if( group >= 0 )
             gal->ChangeGroupColor( group, color );
@@ -787,7 +782,7 @@ void VIEW::UpdateAllLayersColor()
             for( int i = 0; i < layers_count; ++i )
             {
                 const COLOR4D color = m_painter->GetSettings()->GetColor( item, layers[i] );
-                int group = viewData->getGroup( layers[i] );
+                int           group = viewData->getGroup( layers[i] );
 
                 if( group >= 0 )
                     m_gal->ChangeGroupColor( group, color );
@@ -946,8 +941,8 @@ struct VIEW::DRAW_ITEM_VISITOR
         wxCHECK( aItem->viewPrivData(), false );
 
         // Conditions that have to be fulfilled for an item to be drawn
-        bool drawCondition = aItem->viewPrivData()->isRenderable() &&
-                             aItem->ViewGetLOD( layer, view ) < view->m_scale;
+        bool drawCondition = aItem->viewPrivData()->isRenderable()
+                                    && aItem->ViewGetLOD( layer, view ) < view->m_scale;
         if( !drawCondition )
             return true;
 
@@ -962,15 +957,21 @@ struct VIEW::DRAW_ITEM_VISITOR
     void deferredDraw()
     {
         if( reverseDrawOrder )
+        {
             std::sort( drawItems.begin(), drawItems.end(),
-                       []( VIEW_ITEM* a, VIEW_ITEM* b ) -> bool {
+                       []( VIEW_ITEM* a, VIEW_ITEM* b ) -> bool
+                       {
                            return b->viewPrivData()->m_drawPriority < a->viewPrivData()->m_drawPriority;
                        });
+        }
         else
+        {
             std::sort( drawItems.begin(), drawItems.end(),
-                       []( VIEW_ITEM* a, VIEW_ITEM* b ) -> bool {
+                       []( VIEW_ITEM* a, VIEW_ITEM* b ) -> bool
+                       {
                            return a->viewPrivData()->m_drawPriority < b->viewPrivData()->m_drawPriority;
                        });
+        }
 
         for( VIEW_ITEM* item : drawItems )
             view->draw( item, layer );
@@ -1147,11 +1148,13 @@ void VIEW::Redraw()
     rect.Normalize();
     BOX2I recti( rect.GetPosition(), rect.GetSize() );
 
-    // The view rtree uses integer positions.  Large screens can overflow
-    // this size so in this case, simply set the rectangle to the full rtree
-    if( rect.GetWidth() > std::numeric_limits<int>::max() ||
-        rect.GetHeight() > std::numeric_limits<int>::max() )
+    // The view rtree uses integer positions.  Large screens can overflow this size so in
+    // this case, simply set the rectangle to the full rtree.
+    if( rect.GetWidth() > std::numeric_limits<int>::max()
+            || rect.GetHeight() > std::numeric_limits<int>::max() )
+    {
         recti.SetMaximum();
+    }
 
     redrawRect( recti );
 
@@ -1214,13 +1217,9 @@ void VIEW::invalidateItem( VIEW_ITEM* aItem, int aUpdateFlags )
         // updateLayers updates geometry too, so we do not have to update both of them at the
         // same time
         if( aUpdateFlags & LAYERS )
-        {
             updateLayers( aItem );
-        }
         else if( aUpdateFlags & GEOMETRY )
-        {
             updateBbox( aItem );
-        }
     }
 
     int layers[VIEW_MAX_LAYERS], layers_count;
@@ -1376,11 +1375,10 @@ bool VIEW::areRequiredLayersEnabled( int aLayerId ) const
 
     std::set<int>::const_iterator it, it_end;
 
-    for( it = m_layers.at( aLayerId ).requiredLayers.begin(),
-         it_end = m_layers.at( aLayerId ).requiredLayers.end(); it != it_end; ++it )
+    for( int layer : m_layers.at( aLayerId ).requiredLayers )
     {
         // That is enough if just one layer is not enabled
-        if( !m_layers.at( *it ).visible || !areRequiredLayersEnabled( *it ) )
+        if( !m_layers.at( layer ).visible || !areRequiredLayersEnabled( layer ) )
             return false;
     }
 
diff --git a/common/view/view_group.cpp b/common/view/view_group.cpp
index 41bb9a8ea6..1c6a2ec8e9 100644
--- a/common/view/view_group.cpp
+++ b/common/view/view_group.cpp
@@ -2,6 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2013 CERN
+ * Copyright (C) 2021 KiCad Developers, see AUTHORS.txt for contributors.
  * @author Maciej Suminski <maciej.suminski@cern.ch>
  *
  * This program is free software; you can redistribute it and/or
@@ -31,7 +32,7 @@
  */
 
 #include <set>
-#include <algorithm>
+#include <core/kicad_algo.h>
 #include <view/view_group.h>
 #include <view/view.h>
 #include <painter.h>
@@ -61,14 +62,7 @@ void VIEW_GROUP::Add( VIEW_ITEM* aItem )
 
 void VIEW_GROUP::Remove( VIEW_ITEM* aItem )
 {
-    for( auto iter = m_groupItems.begin(); iter != m_groupItems.end(); ++iter )
-    {
-        if( aItem == *iter )
-        {
-            m_groupItems.erase( iter );
-            break;
-        }
-    }
+    alg::delete_matching( m_groupItems, aItem );
 }
 
 
@@ -102,7 +96,7 @@ const BOX2I VIEW_GROUP::ViewBBox() const
     {
         bb = m_groupItems[0]->ViewBBox();
 
-        for( auto item : m_groupItems )
+        for( VIEW_ITEM* item : m_groupItems )
             bb.Merge( item->ViewBBox() );
     }
 
@@ -204,7 +198,7 @@ void VIEW_GROUP::FreeItems()
 }
 
 
-const VIEW_GROUP::ITEMS VIEW_GROUP::updateDrawList() const
+const std::vector<VIEW_ITEM*> VIEW_GROUP::updateDrawList() const
 {
     return m_groupItems;
 }
diff --git a/common/view/view_item.cpp b/common/view/view_item.cpp
index a543e31649..017cfe78f0 100644
--- a/common/view/view_item.cpp
+++ b/common/view/view_item.cpp
@@ -2,6 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2013-2016 CERN
+ * Copyright (C) 2021 KiCad Developers, see AUTHORS.txt for contributors.
  * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
  *
  * This program is free software; you can redistribute it and/or
@@ -22,8 +23,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-#include <gal/definitions.h>
-
 #include <view/view_item.h>
 #include <view/view.h>
 
diff --git a/common/view/view_overlay.cpp b/common/view/view_overlay.cpp
index 50365e8620..2991773c22 100644
--- a/common/view/view_overlay.cpp
+++ b/common/view/view_overlay.cpp
@@ -61,8 +61,9 @@ struct VIEW_OVERLAY::COMMAND_LINE : public VIEW_OVERLAY::COMMAND
 struct VIEW_OVERLAY::COMMAND_RECTANGLE : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_RECTANGLE( const VECTOR2D& aP0, const VECTOR2D& aP1 ) :
-        m_p0( aP0 ), m_p1( aP1 )
-    {}
+        m_p0( aP0 ),
+        m_p1( aP1 )
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -78,7 +79,8 @@ struct VIEW_OVERLAY::COMMAND_CIRCLE : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_CIRCLE( const VECTOR2D& aCenter, double aRadius ) :
         m_center(aCenter),
-        m_radius(aRadius) {}
+        m_radius(aRadius)
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -114,7 +116,8 @@ struct VIEW_OVERLAY::COMMAND_ARC : public VIEW_OVERLAY::COMMAND
 struct VIEW_OVERLAY::COMMAND_POLYGON : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_POLYGON( const std::deque<VECTOR2D>& aPointList ) :
-       m_pointList( aPointList ) {}
+        m_pointList( aPointList )
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -128,7 +131,8 @@ struct VIEW_OVERLAY::COMMAND_POLYGON : public VIEW_OVERLAY::COMMAND
 struct VIEW_OVERLAY::COMMAND_POLY_POLYGON : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_POLY_POLYGON( const SHAPE_POLY_SET& aPolySet ) :
-       m_polySet( aPolySet ) {}
+        m_polySet( aPolySet )
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -161,7 +165,8 @@ struct VIEW_OVERLAY::COMMAND_POINT_POLYGON : public VIEW_OVERLAY::COMMAND
 struct VIEW_OVERLAY::COMMAND_SET_STROKE : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_SET_STROKE( bool aIsStroke ) :
-        m_isStroke( aIsStroke ) {}
+        m_isStroke( aIsStroke )
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -175,7 +180,8 @@ struct VIEW_OVERLAY::COMMAND_SET_STROKE : public VIEW_OVERLAY::COMMAND
 struct VIEW_OVERLAY::COMMAND_SET_FILL : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_SET_FILL( bool aIsFill ) :
-        m_isFill(  aIsFill ) {}
+        m_isFill(  aIsFill )
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -190,7 +196,8 @@ struct VIEW_OVERLAY::COMMAND_SET_COLOR : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_SET_COLOR( bool aIsStroke, const COLOR4D& aColor ) :
         m_isStroke( aIsStroke ),
-        m_color( aColor ) {}
+        m_color( aColor )
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -200,15 +207,16 @@ struct VIEW_OVERLAY::COMMAND_SET_COLOR : public VIEW_OVERLAY::COMMAND
             aView->GetGAL()->SetFillColor( m_color );
     }
 
-    bool m_isStroke;
-    COLOR4D m_color;
+    bool     m_isStroke;
+    COLOR4D  m_color;
 };
 
 
 struct VIEW_OVERLAY::COMMAND_SET_WIDTH : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_SET_WIDTH( double aWidth ) :
-        m_width( aWidth ) {}
+        m_width( aWidth )
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -222,7 +230,8 @@ struct VIEW_OVERLAY::COMMAND_SET_WIDTH : public VIEW_OVERLAY::COMMAND
 struct VIEW_OVERLAY::COMMAND_GLYPH_SIZE : public VIEW_OVERLAY::COMMAND
 {
     COMMAND_GLYPH_SIZE( const VECTOR2D aSize ) :
-        m_size( aSize ) {};
+        m_size( aSize )
+    { };
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -235,11 +244,11 @@ struct VIEW_OVERLAY::COMMAND_GLYPH_SIZE : public VIEW_OVERLAY::COMMAND
 
 struct VIEW_OVERLAY::COMMAND_BITMAP_TEXT : public VIEW_OVERLAY::COMMAND
 {
-    COMMAND_BITMAP_TEXT( const wxString& aText, const VECTOR2D& aPosition,
-                             double aRotationAngle ) :
+    COMMAND_BITMAP_TEXT( const wxString& aText, const VECTOR2D& aPosition, double aRotationAngle ) :
         m_text( aText ),
         m_pos( aPosition ),
-        m_angle (aRotationAngle) {};
+        m_angle (aRotationAngle)
+    { }
 
     virtual void Execute( VIEW* aView ) const override
     {
@@ -264,7 +273,7 @@ VIEW_OVERLAY::~VIEW_OVERLAY()
 
 void VIEW_OVERLAY::releaseCommands()
 {
-    for( auto cmd : m_commands )
+    for( VIEW_OVERLAY::COMMAND* cmd : m_commands )
         delete cmd;
 
     m_commands.clear();
@@ -288,7 +297,7 @@ const BOX2I VIEW_OVERLAY::ViewBBox() const
 
 void VIEW_OVERLAY::ViewDraw( int aLayer, VIEW* aView ) const
 {
-    for( const auto& cmd : m_commands )
+    for( const VIEW_OVERLAY::COMMAND* cmd : m_commands )
         cmd->Execute( aView );
 }
 
@@ -323,10 +332,9 @@ void VIEW_OVERLAY::Polyline( const SHAPE_LINE_CHAIN& aPolyLine )
 {
     SetIsStroke( true );
     SetIsFill( false );
+
     for( int i = 0; i < aPolyLine.SegmentCount(); i++ )
-    {
         Line( aPolyLine.CSegment( i ) );
-    }
 }
 
 
@@ -354,8 +362,8 @@ void VIEW_OVERLAY::Circle( const VECTOR2D& aCenterPoint, double aRadius )
 }
 
 
-void VIEW_OVERLAY::Arc( const VECTOR2D& aCenterPoint,
-                        double aRadius, double aStartAngle, double aEndAngle )
+void VIEW_OVERLAY::Arc( const VECTOR2D& aCenterPoint, double aRadius, double aStartAngle,
+                        double aEndAngle )
 {
     m_commands.push_back( new COMMAND_ARC( aCenterPoint, aRadius, aStartAngle, aEndAngle ) );
 }
diff --git a/include/tool/selection.h b/include/tool/selection.h
index f86f123972..97ae65cc61 100644
--- a/include/tool/selection.h
+++ b/include/tool/selection.h
@@ -2,6 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2013-2017 CERN
+ * Copyright (C) 2021 KiCad Developers, see AUTHORS.txt for contributors.
  * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
  * @author Maciej Suminski <maciej.suminski@cern.ch>
  *
@@ -171,7 +172,7 @@ public:
      */
     bool HasType( KICAD_T aType ) const;
 
-    virtual const VIEW_GROUP::ITEMS updateDrawList() const override;
+    virtual const std::vector<KIGFX::VIEW_ITEM*> updateDrawList() const override;
 
     bool HasReferencePoint() const
     {
diff --git a/include/view/view.h b/include/view/view.h
index 60bd2e0304..99d45049b9 100644
--- a/include/view/view.h
+++ b/include/view/view.h
@@ -645,13 +645,6 @@ public:
             m_dirtyTargets[i] = false;
     }
 
-    /**
-     * Add an item to a list of items that are going to be refreshed upon the next frame rendering.
-     *
-     * @param aItem is the item to be refreshed.
-     */
-    void MarkForUpdate( VIEW_ITEM* aItem );
-
     /**
      * Iterate through the list of items that asked for updating and updates them.
      */
@@ -689,14 +682,6 @@ public:
         m_useDrawPriority = aFlag;
     }
 
-    /**
-     * @return true if draw order is reversed
-     */
-    bool IsDrawOrderReversed() const
-    {
-        return m_reverseDrawOrder;
-    }
-
     /**
      * Only takes effect if UseDrawPriority is true.
      *
@@ -831,40 +816,30 @@ protected:
     std::vector<EDA_ITEM *>            m_ownedItems;
 
     ///< Whether to use rendering order modifier or not.
-    bool m_enableOrderModifier;
+    bool                               m_enableOrderModifier;
 
     ///< The set of possible displayed layers and its properties.
-    std::vector<VIEW_LAYER> m_layers;
+    std::vector<VIEW_LAYER>            m_layers;
 
     ///< Sorted list of pointers to members of m_layers.
-    std::vector<VIEW_LAYER*> m_orderedLayers;
+    std::vector<VIEW_LAYER*>           m_orderedLayers;
 
     ///< Flat list of all items.
     std::shared_ptr<std::vector<VIEW_ITEM*>> m_allItems;
 
     ///< The set of layers that are displayed on the top.
-    std::set<unsigned int> m_topLayers;
+    std::set<unsigned int>             m_topLayers;
 
     ///< Center point of the VIEW (the point at which we are looking at).
-    VECTOR2D m_center;
+    VECTOR2D                           m_center;
 
-    ///< Scale of displayed VIEW_ITEMs.
-    double m_scale;
+    double                             m_scale;
+    BOX2D                              m_boundary;
+    double                             m_minScale;
+    double                             m_maxScale;
 
-    ///< View boundaries.
-    BOX2D m_boundary;
-
-    ///< Scale lower limit.
-    double m_minScale;
-
-    ///< Scale upper limit.
-    double m_maxScale;
-
-    ///< Horizontal flip flag.
-    bool m_mirrorX;
-
-    ///< Vertical flip flag.
-    bool m_mirrorY;
+    bool                               m_mirrorX;
+    bool                               m_mirrorY;
 
     ///< PAINTER contains information how do draw items.
     PAINTER* m_painter;
diff --git a/include/view/view_group.h b/include/view/view_group.h
index 631bb0cb3a..af75b5abcf 100644
--- a/include/view/view_group.h
+++ b/include/view/view_group.h
@@ -51,22 +51,16 @@ public:
 
     /**
      * Return the number of stored items.
-     *
-     * @return Number of stored items.
      */
     virtual unsigned int GetSize() const;
 
     /**
      * Add an item to the group.
-     *
-     * @param aItem is the item to be added.
      */
     virtual void Add( VIEW_ITEM* aItem );
 
     /**
      * Remove an item from the group.
-     *
-     * @param aItem is the item to be removed.
      */
     virtual void Remove( VIEW_ITEM* aItem );
 
@@ -79,8 +73,6 @@ public:
 
     /**
      * Return the bounding box for all stored items covering all its layers.
-     *
-     * @return The current bounding box
      */
     virtual const BOX2I ViewBBox() const override;
 
@@ -102,8 +94,6 @@ public:
 
     /**
      * Set layer used to draw the group.
-     *
-     * @param aLayer is the layer used for drawing.
      */
     inline virtual void SetLayer( int aLayer )
     {
@@ -116,15 +106,11 @@ public:
     void FreeItems();
 
 protected:
-    typedef std::vector<VIEW_ITEM*> ITEMS;
+    virtual const std::vector<VIEW_ITEM*> updateDrawList() const;
 
-    virtual const ITEMS updateDrawList() const;
-
-    ///< Layer on which the group is drawn.
-    int m_layer;
-
-    ///< Container for storing VIEW_ITEMs.
-    ITEMS m_groupItems;
+protected:
+    int                     m_layer;
+    std::vector<VIEW_ITEM*> m_groupItems;
 };
 
 } // namespace KIGFX
diff --git a/include/view/view_item.h b/include/view/view_item.h
index 69561ffe9c..96edccdf0f 100644
--- a/include/view/view_item.h
+++ b/include/view/view_item.h
@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2013-2016 CERN
- * Copyright (C) 2020 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2020-2021 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
  *
@@ -24,11 +24,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-/**
- * @file view_item.h
- * @brief VIEW_ITEM class definition.
- */
-
 #ifndef __VIEW_ITEM_H
 #define __VIEW_ITEM_H
 
diff --git a/pcbnew/tools/pcb_selection.cpp b/pcbnew/tools/pcb_selection.cpp
index 04c0056469..56f61804ce 100644
--- a/pcbnew/tools/pcb_selection.cpp
+++ b/pcbnew/tools/pcb_selection.cpp
@@ -4,7 +4,7 @@
  * Copyright (C) 2013-2017 CERN
  * @author Tomasz Wlostowski <tomasz.wlostowski@cern.ch>
  * @author Maciej Suminski <maciej.suminski@cern.ch>
- * Copyright (C) 2017 KiCad Developers, see CHANGELOG.TXT for contributors.
+ * Copyright (C) 2017-2021 KiCad Developers, see CHANGELOG.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
@@ -24,8 +24,6 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-#include <limits>
-
 #include <functional>
 using namespace std::placeholders;
 
@@ -84,7 +82,7 @@ EDA_ITEM* PCB_SELECTION::GetTopLeftItem( bool aFootprintsOnly ) const
 }
 
 
-const KIGFX::VIEW_GROUP::ITEMS PCB_SELECTION::updateDrawList() const
+const std::vector<KIGFX::VIEW_ITEM*> PCB_SELECTION::updateDrawList() const
 {
     std::vector<VIEW_ITEM*> items;
 
diff --git a/pcbnew/tools/pcb_selection.h b/pcbnew/tools/pcb_selection.h
index c6568569d8..5038e539a1 100644
--- a/pcbnew/tools/pcb_selection.h
+++ b/pcbnew/tools/pcb_selection.h
@@ -1,7 +1,7 @@
 /*
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
- * Copyright (C) 2019 KiCad Developers, see CHANGELOG.TXT for contributors.
+ * Copyright (C) 2019-2021 KiCad Developers, see CHANGELOG.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
@@ -33,7 +33,7 @@ class PCB_SELECTION : public SELECTION
 public:
     EDA_ITEM* GetTopLeftItem( bool aFootprintsOnly = false ) const override;
     
-    const KIGFX::VIEW_GROUP::ITEMS updateDrawList() const override;
+    const std::vector<KIGFX::VIEW_ITEM*> updateDrawList() const override;
 
     const LSET GetSelectionLayers();
 };