function postDivClass($thread)
 {
     $changedObject = $this->mDisplayRevision->getChangeObject();
     $is_changed_thread = $changedObject && $changedObject->id() == $thread->id();
     $class = parent::postDivClass($thread);
     if ($is_changed_thread) {
         return "{$class} lqt_post_changed_by_history";
     } else {
         return $class;
     }
 }