public function render(Varien_Object $row)
 {
     $id = $row->getTriggerId();
     if (!isset(self::$_triggers[$id])) {
         $trigger = Mage::getModel('email/trigger')->load($id);
         if ($trigger->getId()) {
             self::$_triggers[$id] = $trigger->getTitle();
         } else {
             self::$_triggers[$id] = '';
         }
     }
     return self::$_triggers[$id];
 }