anchor.diff:          );
           category = galleryItem.category;
         }
  -      _listItems.add(galleryItem);
  +      listItems.add(galleryItem);
       }
  +    return listItems;
     }
   
     @override
  
positive.code: class GalleryHomeState extends State<GalleryHome> {
    static final Key _homeKey = new ValueKey<String>("Gallery Home");
    static final GlobalKey<ScrollableState> _scrollableKey = new GlobalKey<ScrollableState>();
    final List<Widget> _listItems = <Widget>[];
  
    @override
    void initState() {
      super.initState();
  
      final ThemeData themeData = Theme.of(context);
      final TextStyle headerStyle = themeData.textTheme.body2.copyWith(color: themeData.accentColor);
      String category;
      for (GalleryItem galleryItem in kAllGalleryItems) {
        if (category != galleryItem.category) {
          if (category != null)
            _listItems.add(new Divider());
          _listItems.add(
            new Container(
              height: 48.0,
              padding: const EdgeInsets.only(left: 16.0),
  
negative.code:       body: new Block(
         scrollableKey: _scrollableKey,
         padding: new EdgeInsets.only(top: _kFlexibleSpaceMaxHeight + statusBarHeight),
         children: _galleryListItems()
        )
      );
    }
  