/**
  * Method to work around bug where Hierarchy.php directly refers to
  * ShowInMenus, which is only available on SiteTree
  *
  * @param DataObject $node
  * @return DataObjectSet
  */
 protected function childrenOfNode($node)
 {
     $result = $node->stageChildren(true);
     if (isset($result)) {
         foreach ($result as $child) {
             if (!$child->canView()) {
                 $result->remove($child);
             }
         }
     }
     return $result;
 }