anchor.diff:  class StocksApp extends App {
   
     DrawerController _drawerController = new DrawerController();
  -  PopupMenuController _menuController = new PopupMenuController();
  +  PopupMenuController _menuController;
   
     static Style _style = new Style('''
       display: flex;
  
positive.code: 
    void _handleMenuClick(_) {
      setState(() {
        _menuController.open();
      });
    }
  
negative.code: 
      var toolbar = new ActionBar(
        children: [
          new EventTarget(
            new Icon(key: 'menu', style: _iconStyle,
                size: 24,
                type: 'navigation/menu_white'),
            onGestureTap: _drawerController.toggle
          ),
          new Container(
            style: _titleStyle,
            children: [title]
          ),
          new EventTarget(
            new Icon(key: 'search', style: _iconStyle,
                size: 24,
                type: 'action/search_white'),
            onGestureTap: _handleSearchClick
          ),
          new EventTarget(
            new Icon(key: 'more_white', style: _iconStyle,
                size: 24,
                type: 'navigation/more_vert_white'),
            onGestureTap: _handleMenuClick
          )
        ]
      );
  
  