protected function getRelationApiEndpoint()
    {
        // build class name
        $class = $this->_query->modelClass;
        // fetch menu api detail from endpoint name
        $menu = Yii::$app->adminmenu->getApiDetail($class::ngRestApiEndpoint());
        
        if (!$menu) {
            throw new InvalidConfigException("Unable to find the API endpoint, maybe insufficent permission or missing admin module context (admin module prefix).");
        }
        
        // @todo what about: admin/
        return 'admin/'.$menu['permissionApiEndpoint'];
    }