protected static function _requiredLevels($componentClass)
 {
     $requiredLevels = parent::_requiredLevels($componentClass);
     $generators = Kwc_Abstract::getSetting($componentClass, 'generators');
     while (isset($generators['subMenu'])) {
         $class = $generators['subMenu']['component']['subMenu'];
         if (!is_instance_of($class, 'Kwc_Menu_Abstract_Component')) {
             break;
         }
         $generators = Kwc_Abstract::getSetting($class, 'generators');
         $requiredLevels++;
     }
     return $requiredLevels;
 }