anchor.diff:    html.DivElement _rootListDiv;
     html.UListElement _rootList;
     html.Element _outlineButton;
  +
  +  final List<html.CssStyleRule> _outlineItemCssRules = [];
   
     final PreferenceStore _prefs;
     bool _visible = true;
  
positive.code:         _outlineDiv.classes.add('collapsed');
        }
      });
    }
  
    Stream<OutlineItem> get onChildSelected => _childSelectedController.stream;
  
negative.code:       _element.append(_typeSpan);
      }
  
      _element.classes.add("${Outline._ITEM_CSS_CLASS} ${cssClassName}");
    }
  
    String get displayName => _data.name;
  