@Override
      public void mouseDragged(MouseEvent event) {
        Object component = event.getSource();
        // DnDManagerImpl.SOURCE_KEY
        Object property = component instanceof Component ? ClientProperty.get((Component)component, "DnD Source") : null;
        if (property == null) {
          // use Swing-based DnD only if custom DnD is not set
          super.mouseDragged(event);
        }
      }
@Override
      public void mouseDragged(MouseEvent event)