/**
  * Checks whether this feature should be displayed for the current user
  * in current disscussion.
  * By default, this checks the discussions's can_manage function and that
  * the discussion isn't deleted.
  * @param forum_discussion $discussion
  * @return bool True if this should display
  */
 public function should_display($discussion)
 {
     return $discussion->can_manage() && !$discussion->is_deleted();
 }