@Override
  public void propertyChange(PropertyChangeEvent evt) {
    if (evt.getPropertyName().equals(JTree.TREE_MODEL_PROPERTY)){
      ((TreeModel)evt.getOldValue()).removeTreeModelListener(this);
      ((TreeModel)evt.getNewValue()).addTreeModelListener(this);
    }
  }
@Override
  public void propertyChange(PropertyChangeEvent evt)