return (tree.getSelectionModel().getSelectionMode() == TreeSelectionModel.CONTIGUOUS_TREE_SELECTION);
return (tree.getSelectionModel().getSelectionMode() != TreeSelectionModel.SINGLE_TREE_SELECTION) && ((event.getModifiersEx() & InputEvent.SHIFT_DOWN_MASK) != 0);
  protected boolean isMultiSelectEvent(MouseEvent event)  {    return (tree.getSelectionModel().getSelectionMode() == TreeSelectionModel.CONTIGUOUS_TREE_SELECTION);  }