Flutter Provider get Map changes with Selector

try to use Map with Selector (StreamProvider on the top), but it does not get the changes in the Map. When I change Map to List all works and widget is rebuild

      Widget build(BuildContext context) {
super.build(context);
return Selector<Map<String, ItemWebModel>, String>(selector: (_, itemMap) {
  return _isItemInMap(itemMap);
},
    builder: (_, _imageUrl, __) {