protected override void OnDrop(DragItemsEventArgs args)
 {
 }
 protected override void OnDragEnter(DragItemsEventArgs args)
 {
     if (args.Items.Count() > 0 && args.Items.Any(c => c is SwimlaneShapeBase))
         base.OnDragEnter(args);
 }
 protected override void OnDragEnter(DragItemsEventArgs args)
 {
     if (args.Items.Count() > 0 && !args.Items.Any(c => c is CustomContainerBase))
         base.OnDragEnter(args);
 }