@Nullable
  private static Object getPathElement(final TreePath selectionPath) {
    if (selectionPath == null) {
      return null;
    }
    final DefaultMutableTreeNode lastPathComponent = (DefaultMutableTreeNode)selectionPath.getLastPathComponent();
    if (lastPathComponent == null) {
      return null;
    }
    final Object userObject = lastPathComponent.getUserObject();
    if (!(userObject instanceof NodeDescriptor)) {
      return null;
    }
    final Object element = ((NodeDescriptor<?>)userObject).getElement();
    if (!(element instanceof LibraryTableTreeContentElement)) {
      return null;
    }
    return element;
  }
@Nullable
  private static Object getPathElement(final TreePath selectionPath)