anchor.diff:          style: typography.error, // if you see this, you've forgotten to correctly configure the text style!
           child: new TaskDescription(
             label: 'Address Book',
  -          child: new Focus(
  -            initialFocus: nameKey,
  -            child: buildMain()
  -          )
  +          child: new Navigator(_navigationState)
           )
         )
       );
  
positive.code: import 'package:sky/theme/typography.dart' as typography;
  import 'package:sky/widgets/basic.dart';
  import 'package:sky/widgets/default_text_style.dart';
  import 'package:sky/widgets/floating_action_button.dart';
  import 'package:sky/widgets/focus.dart';
  import 'package:sky/widgets/icon.dart';
  import 'package:sky/widgets/icon_button.dart';
  import 'package:sky/widgets/material.dart';
  import 'package:sky/widgets/scaffold.dart';
  import 'package:sky/widgets/scrollable_viewport.dart';
  import 'package:sky/widgets/task_description.dart';
  
negative.code: 
  class AddressBookApp extends App {
  
    Widget buildToolBar(Navigator navigator) {
      return new ToolBar(
          left: new IconButton(icon: "navigation/arrow_back"),
          right: [new IconButton(icon: "navigation/check")]
        );
    }
  
    Widget buildFloatingActionButton(Navigator navigator) {
      return new FloatingActionButton(
        child: new Icon(type: 'image/photo_camera', size: 24),
        backgroundColor: Theme.of(this).accentColor,
        onPressed: () {
          showDialog = true;
          navigator.pushState(this, (_) {
            showDialog = false;
          });
        }
      );
    }
  
  