anchor.diff:  
   Click the back icon in the toolbar to navigate back to the heroes list. If you made any changes in the hero detail editor, they should be shown in the heroes list right away.
   
  +=== Nice touches in the AppComponent
  +
  +Here are the UX-related changes to AppComponent explained.
  +
  +==== Dynamic toolbar title
  +
  +We add the `title` property to the `AppComponent` and bind it to the text content of `<div title spacer></div>` inside the toolbar in the template.
  +
  +Instead of a static title, the title is now updated dynamically. We subscribe to the `Router` in `AppComponent` and use `RouteData` in the navigation event callback to get the title value specified for the current route. Each time after user opens the application or navigates inside, the `Router` event is dispatched so the `title` property is updated.
  +
  +==== The back icon in the toolbar
  +
  +We add `<paper-icon-button>` to have a back icon inside the `<app-toolbar>` in the template. The icon has a click event binding, which calls `goBack()` method of `AppComponent`. In the method, we invoke `navigate` method of the router to navigate back to the heroes list from the hero detail.
  +
  +When the heroes list is shown, the back icon is useless, so we need to hide it. To achieve that, we added `isInChildView` property to `AppComponent`, which is updated from the route data in the navigation event callback. In the template we add `*ngIf="isInChildView"` for the `<paper-icon-button>`.
  +
  +We also add a few positioning style rules for the `paper-icon-button`.
  +
  +==== Dynamic toolbar shadow
  +
  +To make the toolbar look better, we make the application toolbar to have a shadow that is shown only for the hero detail view, but not for the heroes list view. For this purpose we bind the `raised` class of the `<app-toolbar>` to `isInChildView` property and add a style rule which applies the shadow mixin from `paper-styles` to the `<app-toolbar>` when it has the `raised` class.
  +
   == Wrap-up
   
   All the tutorial steps are complete. Now you can use all powers of Polymer elements in your Angular 2 applications and know how to do it.
  
positive.code: bower install
  ----
  
  After that, in your project root you should have `bower_components` directory with all elements declared by bower.json together with the elements’ requirements. Verify that:
  
  [source,bash]
  ----
  ls bower_components
  ----
  
  .Output
  ----
  app-layout
  font-roboto
  
negative.code: 
  === Npm dependency
  
  Alongside with bower dependencies, we also need to add one npm dependency to the project. `@vaadin/angular2-polymer` package adds support for Polymer elements in Angular 2 component templates. Run this command to install the package and save the dependency in `package.json` at the same time:
  
  [source,bash]
  ----
  