updateUI();
  public void setModel(TreeModel model)  {    if (treeModel == model)      return;    // add treeModelListener to the new model    if (treeModelListener == null)      treeModelListener = createTreeModelListener();    if (model != null) // as setModel(null) is allowed      model.addTreeModelListener(treeModelListener);    TreeModel oldValue = treeModel;    treeModel = model;    firePropertyChange(TREE_MODEL_PROPERTY, oldValue, model);    updateUI();  }