code: @Override
      public void dragOver(final DragEvent dragEvent) {
          // System.out.println("drag OVER");
  
          if (dragEvent.getGestureSource() != controller().view().getBox()
                  && dragEvent.getDragboard().hasContent(CustomDataFormat.DOCKABLE)) {
  
              dragEvent.acceptTransferModes(TransferMode.MOVE);
  
              controller().view().drawMarker((ToggleButton) dragEvent.getGestureSource(), dragEvent.getX(), dragEvent.getY());
  
              dragEvent.consume();
          }
  
      }
docs: {@inheritDoc}