anchor.diff:            ),
           ),
         ),
  -      body: IndexedStack(
  -          index: widget.selectedIndex, children: widget.currentTabs),
  +      body: IndexedStack(index: selectedIndex, children: widget.currentTabs),
         bottomNavigationBar: BottomNavigationBar(
           type: BottomNavigationBarType.fixed,
           onTap: (index) {
             setState(() {
  -            widget.selectedIndex = index;
  +            selectedIndex = index;
               _sendCurrentTabToAnalytics();
             });
           },
  +        currentIndex: selectedIndex,
           items: [
             BottomNavigationBarItem(
               icon: new Icon(Icons.home),
  
positive.code: 
    void _sendCurrentTabToAnalytics() {
      observer.analytics.setCurrentScreen(
        screenName:
            '${BottomTabBar.routeName}/${widget.tabNames[widget.selectedIndex]}',
      );
    }
  }
  
negative.code:     Profile(),
    ];
  
    final List<String> tabNames = ['home', 'maps', 'notifications', 'profile'];
  
    @override
  