public function getPersistentDataKey($key, $salt = null)
 {
     $append = '';
     $model = Mage::registry('ew:current_message');
     if (is_object($model)) {
         $append .= $model->getId();
     }
     return parent::getPersistentDataKey($key, (string) $append);
 }
 public function getPersistentDataKey($key, $salt = null)
 {
     $append = '';
     $model = '';
     if (is_object($model)) {
         $append .= $model->getId();
     }
     return parent::getPersistentDataKey($key, (string) $append);
 }
 public function getPersistentDataKey($key, $salt = null)
 {
     $append = '';
     return parent::getPersistentDataKey($key, (string) $append);
 }