anchor.diff:  
     @override
     Widget build(BuildContext context) {
  -    super.build(context);
       if (_files == null) {
         return Center(child: CircularProgressIndicator());
       }
  
positive.code: }
  
  class _BrowserState extends State<Browser> with AutomaticKeepAliveClientMixin {
    List<dto.CollectionFile> _files;
  
    @override
    void initState() {
      super.initState();
      _browseTo('');
    }
  
    _browseTo(String path) async {
  
negative.code:       },
      );
    }
  }
  
  final _pathSeparatorRegExp = RegExp(r'[/\\]');
  