static function getListableObjectTypeIds()
 {
     if (is_null(self::$listableObjectTypesIds)) {
         $ids = array();
         $sql = "\r\n\t\t\t\tSELECT DISTINCT(id) as id  \r\n\t\t\t\tFROM " . TABLE_PREFIX . "object_types \r\n\t\t\t\tWHERE type IN ('content_object', 'dimension_object', 'comment') AND (\r\n\t\t\t\t\tplugin_id IS NULL OR \r\n\t\t\t\t\tplugin_id = 0 OR \r\n\t\t\t\t\tplugin_id IN ( \r\n\t\t\t\t\t\tSELECT id FROM " . TABLE_PREFIX . "plugins WHERE is_activated > 0 AND is_installed > 0 \r\n\t\t\t\t\t)\r\n\t\t\t\t)";
         $rows = DB::executeAll($sql);
         foreach ($rows as $row) {
             $ids[array_var($row, 'id')] = array_var($row, 'id');
         }
         self::$listableObjectTypesIds = $ids;
     }
     return self::$listableObjectTypesIds;
 }