diff --git a/eeschema/sch_commit.cpp b/eeschema/sch_commit.cpp
index fe051b71e2..33b0b5fdc0 100644
--- a/eeschema/sch_commit.cpp
+++ b/eeschema/sch_commit.cpp
@@ -283,7 +283,10 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
             }
 
             if( schItem->Type() == SCH_GROUP_T )
+            {
+                wxASSERT_MSG( !addedGroup, "Multiple groups in a single commit. This is not supported." );
                 addedGroup = static_cast<SCH_GROUP*>( schItem );
+            }
 
             if( frame )
                 frame->UpdateItem( schItem, true, true );
@@ -374,6 +377,12 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
                 ent.m_copy = nullptr;   // We've transferred ownership to the undo list
             }
 
+            if( schItem->Type() == SCH_GROUP_T )
+            {
+                wxASSERT_MSG( !addedGroup, "Multiple groups in a single commit. This is not supported." );
+                addedGroup = static_cast<SCH_GROUP*>( schItem );
+            }
+
             if( frame )
                 frame->UpdateItem( schItem, false, true );
 
diff --git a/pcbnew/board_commit.cpp b/pcbnew/board_commit.cpp
index f0e5ee28bf..d531210500 100644
--- a/pcbnew/board_commit.cpp
+++ b/pcbnew/board_commit.cpp
@@ -320,7 +320,10 @@ void BOARD_COMMIT::Push( const wxString& aMessage, int aCommitFlags )
             }
 
             if( boardItem->Type() == PCB_GROUP_T || boardItem->Type() == PCB_GENERATOR_T )
+            {
+                wxASSERT_MSG( !addedGroup, "Multiple groups in a single commit. This is not supported." );
                 addedGroup = static_cast<PCB_GROUP*>( boardItem );
+            }
 
             if( boardItem->Type() != PCB_MARKER_T )
                 propagateDamage( boardItem, staleZones );
@@ -467,6 +470,12 @@ void BOARD_COMMIT::Push( const wxString& aMessage, int aCommitFlags )
                 connectivity->Update( boardItem );
             }
 
+            if( boardItem->Type() == PCB_GROUP_T || boardItem->Type() == PCB_GENERATOR_T )
+            {
+                wxASSERT_MSG( !addedGroup, "Multiple groups in a single commit. This is not supported." );
+                addedGroup = static_cast<PCB_GROUP*>( boardItem );
+            }
+
             if( boardItem->Type() != PCB_MARKER_T )
             {
                 propagateDamage( boardItemCopy, staleZones );   // before