diff --git a/pcbnew/connectivity/connectivity_algo.cpp b/pcbnew/connectivity/connectivity_algo.cpp
index a64a071bc2..fa8b251083 100644
--- a/pcbnew/connectivity/connectivity_algo.cpp
+++ b/pcbnew/connectivity/connectivity_algo.cpp
@@ -226,6 +226,12 @@ void CN_CONNECTIVITY_ALGO::searchConnections()
 
     m_itemList.RemoveInvalidItems( garbage );
 
+    if( m_isLocal )
+    {
+        for( CN_ITEM* item : m_globalConnectivity->m_itemList )
+            item->RemoveInvalidRefs();
+    }
+
     for( CN_ITEM* item : garbage )
         delete item;
 
@@ -542,9 +548,13 @@ void CN_CONNECTIVITY_ALGO::Build( BOARD* aBoard, PROGRESS_REPORTER* aReporter )
 }
 
 
-void CN_CONNECTIVITY_ALGO::LocalBuild( const std::vector<BOARD_ITEM*>& aItems )
+void CN_CONNECTIVITY_ALGO::LocalBuild( std::shared_ptr<CN_CONNECTIVITY_ALGO> aGlobalConnectivity,
+                                       const std::vector<BOARD_ITEM*>& aLocalItems )
 {
-    for( BOARD_ITEM* item : aItems )
+    m_isLocal = true;
+    m_globalConnectivity = aGlobalConnectivity;
+
+    for( BOARD_ITEM* item : aLocalItems )
     {
         switch( item->Type() )
         {
diff --git a/pcbnew/connectivity/connectivity_algo.h b/pcbnew/connectivity/connectivity_algo.h
index 511b5fb04e..32db07c22f 100644
--- a/pcbnew/connectivity/connectivity_algo.h
+++ b/pcbnew/connectivity/connectivity_algo.h
@@ -154,8 +154,14 @@ public:
         std::list<CN_ITEM*> m_items;
     };
 
-    CN_CONNECTIVITY_ALGO() {}
-    ~CN_CONNECTIVITY_ALGO() { Clear(); }
+    CN_CONNECTIVITY_ALGO() :
+            m_isLocal( false )
+    {}
+
+    ~CN_CONNECTIVITY_ALGO()
+    {
+        Clear();
+    }
 
     bool ItemExists( const BOARD_CONNECTED_ITEM* aItem ) const
     {
@@ -197,8 +203,9 @@ public:
         return m_dirtyNets.size();
     }
 
-    void Build( BOARD* aZoneLayer, PROGRESS_REPORTER* aReporter = nullptr );
-    void LocalBuild( const std::vector<BOARD_ITEM*>& aItems );
+    void Build( BOARD* aBoard, PROGRESS_REPORTER* aReporter = nullptr );
+    void LocalBuild( std::shared_ptr<CN_CONNECTIVITY_ALGO> aGlobalConnectivity,
+                     const std::vector<BOARD_ITEM*>& aLocalItems );
 
     void Clear();
 
@@ -272,6 +279,9 @@ private:
     std::vector<std::shared_ptr<CN_CLUSTER>>              m_ratsnestClusters;
     std::vector<bool>                                     m_dirtyNets;
 
+    bool                                                  m_isLocal;
+    std::shared_ptr<CN_CONNECTIVITY_ALGO>                 m_globalConnectivity;
+
     PROGRESS_REPORTER* m_progressReporter = nullptr;
 };
 
diff --git a/pcbnew/connectivity/connectivity_data.cpp b/pcbnew/connectivity/connectivity_data.cpp
index 8129c91421..3750475b6d 100644
--- a/pcbnew/connectivity/connectivity_data.cpp
+++ b/pcbnew/connectivity/connectivity_data.cpp
@@ -44,7 +44,8 @@
 #include <trigo.h>
 #include <drc/drc_rtree.h>
 
-CONNECTIVITY_DATA::CONNECTIVITY_DATA()
+CONNECTIVITY_DATA::CONNECTIVITY_DATA() :
+        m_skipRatsnestUpdate( false )
 {
     m_connAlgo.reset( new CN_CONNECTIVITY_ALGO );
     m_progressReporter = nullptr;
@@ -52,10 +53,12 @@ CONNECTIVITY_DATA::CONNECTIVITY_DATA()
 }
 
 
-CONNECTIVITY_DATA::CONNECTIVITY_DATA( const std::vector<BOARD_ITEM*>& aItems, bool aSkipRatsnest )
-    : m_skipRatsnest( aSkipRatsnest )
+CONNECTIVITY_DATA::CONNECTIVITY_DATA( std::shared_ptr<CONNECTIVITY_DATA> aGlobalConnectivity,
+                                      const std::vector<BOARD_ITEM*>& aLocalItems,
+                                      bool aSkipRatsnestUpdate ) :
+        m_skipRatsnestUpdate( aSkipRatsnestUpdate )
 {
-    Build( aItems );
+    Build( aGlobalConnectivity, aLocalItems );
     m_progressReporter = nullptr;
     m_fromToCache.reset( new FROM_TO_CACHE );
 }
@@ -140,7 +143,8 @@ bool CONNECTIVITY_DATA::Build( BOARD* aBoard, PROGRESS_REPORTER* aReporter )
 }
 
 
-void CONNECTIVITY_DATA::Build( const std::vector<BOARD_ITEM*>& aItems )
+void CONNECTIVITY_DATA::Build( std::shared_ptr<CONNECTIVITY_DATA>& aGlobalConnectivity,
+                               const std::vector<BOARD_ITEM*>& aLocalItems )
 {
     std::unique_lock<KISPINLOCK> lock( m_lock, std::try_to_lock );
 
@@ -148,7 +152,7 @@ void CONNECTIVITY_DATA::Build( const std::vector<BOARD_ITEM*>& aItems )
         return;
 
     m_connAlgo.reset( new CN_CONNECTIVITY_ALGO );
-    m_connAlgo->LocalBuild( aItems );
+    m_connAlgo->LocalBuild( aGlobalConnectivity->GetConnectivityAlgo(), aLocalItems );
 
     internalRecalculateRatsnest();
 }
@@ -272,7 +276,7 @@ void CONNECTIVITY_DATA::internalRecalculateRatsnest( BOARD_COMMIT* aCommit  )
 
     m_connAlgo->ClearDirtyFlags();
 
-    if( !m_skipRatsnest )
+    if( !m_skipRatsnestUpdate )
         updateRatsnest();
 }
 
diff --git a/pcbnew/connectivity/connectivity_data.h b/pcbnew/connectivity/connectivity_data.h
index 3ca4975258..f53e3e38e5 100644
--- a/pcbnew/connectivity/connectivity_data.h
+++ b/pcbnew/connectivity/connectivity_data.h
@@ -88,7 +88,8 @@ public:
     CONNECTIVITY_DATA();
     ~CONNECTIVITY_DATA();
 
-    CONNECTIVITY_DATA( const std::vector<BOARD_ITEM*>& aItems, bool aSkipItems = false );
+    CONNECTIVITY_DATA( std::shared_ptr<CONNECTIVITY_DATA> aGlobalConnectivity,
+                       const std::vector<BOARD_ITEM*>& aLocalItems, bool                               aSkipRatsnestUpdate = false );
 
     /**
      * Function Build()
@@ -100,7 +101,8 @@ public:
      * Function Build()
      * Builds the connectivity database for a set of items aItems.
      */
-    void Build( const std::vector<BOARD_ITEM*>& aItems );
+    void Build( std::shared_ptr<CONNECTIVITY_DATA>& aGlobalConnectivity,
+                const std::vector<BOARD_ITEM*>& aLocalItems );
 
     /**
      * Function Add()
@@ -297,7 +299,7 @@ private:
     std::vector<RN_NET*>            m_nets;
 
     /// Used to suppress ratsnest calculations on dynamic ratsnests
-    bool                            m_skipRatsnest = false;
+    bool                            m_skipRatsnestUpdate;
 
     KISPINLOCK                      m_lock;
 
diff --git a/pcbnew/router/router_tool.cpp b/pcbnew/router/router_tool.cpp
index 396ad3b7ae..bf9d1832c0 100644
--- a/pcbnew/router/router_tool.cpp
+++ b/pcbnew/router/router_tool.cpp
@@ -2099,7 +2099,8 @@ int ROUTER_TOOL::InlineDrag( const TOOL_EVENT& aEvent )
             courtyardClearanceDRC.m_FpInMove.push_back( footprint );
         }
 
-        dynamicData = std::make_unique<CONNECTIVITY_DATA>( dynamicItems, true );
+        dynamicData = std::make_unique<CONNECTIVITY_DATA>( board()->GetConnectivity(),
+                                                           dynamicItems, true );
         connectivityData->BlockRatsnestItems( dynamicItems );
     }
     else
diff --git a/pcbnew/tools/board_inspection_tool.cpp b/pcbnew/tools/board_inspection_tool.cpp
index 161432b116..a69023b97e 100644
--- a/pcbnew/tools/board_inspection_tool.cpp
+++ b/pcbnew/tools/board_inspection_tool.cpp
@@ -1724,7 +1724,7 @@ void BOARD_INSPECTION_TOOL::calculateSelectionRatsnest( const VECTOR2I& aDelta )
 
     if( !m_dynamicData )
     {
-        m_dynamicData = new CONNECTIVITY_DATA( items, true );
+        m_dynamicData = new CONNECTIVITY_DATA( board()->GetConnectivity(), items, true );
         connectivity->BlockRatsnestItems( items );
     }
     else