Fix undo issue primarily with libedit.

Fixes: lp:1797900
* https://bugs.launchpad.net/kicad/+bug/1797900

common/legacy_gal/block.cpp

@@ -148,18 +148,21 @@ void BLOCK_SELECTOR::InitData( EDA_DRAW_PANEL* aPanel, const wxPoint& startpos )
 void BLOCK_SELECTOR::ClearItemsList()
 {
     m_items.ClearItemsList();
+    m_appendUndo = false;
 }
 
 
 void BLOCK_SELECTOR::ClearListAndDeleteItems()
 {
      m_items.ClearListAndDeleteItems();
+     m_appendUndo = false;
 }
 
 
 void BLOCK_SELECTOR::PushItem( ITEM_PICKER& aItem )
 {
     m_items.PushItem( aItem );
+    m_appendUndo = false;
 }
 
 

eeschema/libedit/block_libedit.cpp

@@ -440,30 +440,28 @@ void LIB_EDIT_FRAME::HandleBlockPlace( wxDC* DC )
     case BLOCK_DRAG_ITEM:
     case BLOCK_MOVE:                // Move
     case BLOCK_DUPLICATE:           // Duplicate
-        block->ClearItemsList();
-
         if( GetCurPart() && !block->AppendUndo() )
             SaveCopyInUndoList( GetCurPart() );
 
         pt = block->GetMoveVector();
-        //pt.y *= -1;
 
         if( GetCurPart() )
             BlockMoveSelectedItems( pt, GetCurPart(), block );
 
+        block->ClearItemsList();
         m_canvas->Refresh( true );
         break;
 
     case BLOCK_PASTE:       // Paste (recopy the last block saved)
-        block->ClearItemsList();
-
         if( GetCurPart() )
             SaveCopyInUndoList( GetCurPart() );
 
         pt = block->GetMoveVector();
-        //pt.y = -pt.y;
 
         pasteClipboard( pt );
+
+        block->ClearItemsList();
+        m_canvas->Refresh( true );
         break;
 
     case BLOCK_ZOOM:        // Handled by HandleBlockEnd