anchor.diff:    final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
     final GlobalKey<ScrollableState> _scrollableKey = new GlobalKey<ScrollableState>();
     final TextStyle menuItemStyle = new PestoStyle(fontSize: 15.0, color: Colors.black54, height: 24.0/15.0);
  +  final Object _disableHeroTransition = new Object();
   
     double _getAppBarHeight(BuildContext context) => MediaQuery.of(context).size.height * 0.3;
   
  
positive.code:       scrollableKey: _scrollableKey,
        appBarBehavior: AppBarBehavior.scroll,
        appBar: new AppBar(
          expandedHeight: _getAppBarHeight(context),
          backgroundColor: Colors.transparent,
          elevation: 0,
  
negative.code:             ]
            )
          ],
        ),
        body: _buildContainer(context)
      );
  