public function getItemIds($count = null, $offset = null)
 {
     if ($this->_getSetting('hideCategoriesWithoutEntries')) {
         $select = $this->_getSelect();
         if (!$select) {
             return array();
         }
         if ($count) {
             $select->limit($count, $offset);
         }
         $items = $this->_getItems($select);
         $ret = array();
         foreach ($items as $item) {
             if ($item->listCount) {
                 $ret[] = $item->row->id;
             }
         }
         return $ret;
     } else {
         return parent::getItemIds($count, $offset);
     }
 }