function create_sub_node($id, $values)
 {
     if ($node_id = parent::create_sub_node($id, $values)) {
         $this->expand_node($id);
     }
     return $node_id;
 }
 function limb_tree()
 {
     parent::nested_db_tree();
     $this->_expanded_parents =& session::get('tree_expanded_parents');
     $this->check_expanded_parents();
 }