@Nullable
  protected static HierarchyNodeDescriptor getDescriptor(@NotNull DefaultMutableTreeNode node) {
    Object userObject = node.getUserObject();
    if (userObject instanceof HierarchyNodeDescriptor) {
      return (HierarchyNodeDescriptor)userObject;
    }
    return null;
  }
@Nullable
  protected static HierarchyNodeDescriptor getDescriptor(@NotNull DefaultMutableTreeNode node)