@Override
  protected Enumeration<TreePath> getDescendantToggledPaths(TreePath parent) {
    if (expandImpl != null) {
      return expandImpl.getDescendantToggledPaths(parent);
    }
    else {
      return super.getDescendantToggledPaths(parent);
    }
  }
@Override
  protected Enumeration<TreePath> getDescendantToggledPaths(TreePath parent)