public function actionMoveAfter($moveItemId, $droppedAfterItemId)
    {
        $result = Nav::moveToAfter($moveItemId, $droppedAfterItemId);
        
        if ($result !== true) {
            Yii::$app->response->setStatusCode(422, 'Found URL alias duplication in drop target "'.$result['title'].'".');
        }
        
        return ['success' => $result];
    }