public function markById($id, $open=false, $className=null) {
        if(isset($this->markedNodes[$className.'_'.$id])) {
            $this->markChildren($this->markedNodes[$className.'_'.$id]);
            if($open) {
                $this->markedNodes[$className.'_'.$id]->markOpened();
            }
            
            return true;
        } else {
            return false;
        }
    }