/**
  * Displays discussion list features for this forum. Features are the
  * plugins in the 'feature' subfolder - basically a row of buttons along
  * the bottom.
  * @param int $groupid Group ID
  * @return string HTML code for discussion list features
  */
 public function display_discussion_list_features($groupid)
 {
     // Print discussion list feature buttons (userposts button)
     $features = '';
     foreach (discussion_list_feature::get_all() as $feature) {
         if ($feature->should_display($this, $groupid)) {
             $features .= $feature->display($this, $groupid);
         }
     }
     if ($features) {
         return '<div id="forumng-features">' . $features . '</div>';
     } else {
         return '';
     }
 }