if( getTargetEditPart() == null || getTargetEditPart().getModel() instanceof LibraryHandle)
if ( getTargetEditPart( ) == null )
	public void dragOver( DropTargetEvent event )	{		super.dragOver( event );		if( getTargetEditPart() == null ||				getTargetEditPart().getModel() instanceof LibraryHandle)		{			event.detail = DND.DROP_NONE;		}	}