anchor.diff:  
     Map<String, Note> get _noteStorage => _noteSync.map;
   
  -  void _onNoteSyncChanged(List<ChangeRecord> records) {
  -    var forwardProps = records
  -        .where((ChangeRecord cr) => cr is PropertyChangeRecord)
  -        .map((pcr) => pcr.field)
  -        .where((Symbol field) => _NOTE_SYNC_FORWARD_PROPS.contains(field))
  -        .toList();
  -
  -    for(var matchField in forwardProps) {
  -      _notifyChange(matchField);
  -    }
  +  void _onNoteSyncIsUpdated(PropertyChangeRecord record) {
  +    _notifyChange(const Symbol('isUpdated'));
     }
   
     void _updateNotesList() {
  
positive.code:     }
  
      // TODO: hold onto the subscription. Support dispose?
      _noteSync.changes.listen(_onNoteSyncChanged);
  
      _updateNotesList();
    }
  
negative.code:   void _notifyChange(Symbol prop) {
      notifyChange(new PropertyChangeRecord(prop));
    }
  }
  