How to close a child page by clicking on a TabItem

Please help navigate the bottomNavigationBar Scaffold property. I have a bottom navigation bar with four tabs. They work well, on every screen, but if inside a tab I open a new screen, then clicking on the same navbar tab does not close the child screen, but the state of the parent screen of the tab is updated. How do I close the child screen? Are there any ways? The bottom navigation implementation is simple:

final List<TabItem> tabs = [
    TabItem(
      label: '-',
      icon: 'assets/bottom/search.svg',
      maintainState: false,
      root: 'search',
    ),
    TabItem(
      label: '-',
      icon: 'assets/bottom/news.svg',
      maintainState: false,
      root: 'news',
    ),
    TabItem(
      label: '-',
      icon: 'assets/bottom/messages.svg',
      maintainState: false,
      root: 'messagePage',
    ),
    /*if (Platform.isAndroid)
      TabItem(
        label: '-',
        icon: 'assets/bottom/anonim.svg',
        maintainState: false,
        root: 'dumbDate',
      ),*/
    TabItem(
      label: '-',
      icon: 'assets/bottom/profile.svg',
      maintainState: false,
      root: 'myProfile',
    ),
  ];

  void selectTab(int index, {Map arguments}) {
    if (index == TabNavigator.currentTab.value ||
        index != TabNavigator.currentTab.value) {
      print('Экран обновился');
      setState(() {
        TabNavigator.currentTab.value = index;
      });

      //TabNavigator.changeValue(index);

      //TabNavigator.changeValue(index);
    }
  }

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
        key: childkey,
        onWillPop: () => showDialog<bool>(
              context: context,
              builder: (c) => AlertDialog(
                title: Text('Arbue'),
                content: Text('Вы действительно хотите закрыть приложение?'),
                actions: [
                  FlatButton(
                    child: Text('Да'),
                    onPressed: () => Navigator.pop(c, true),
                  ),
                  FlatButton(
                    child: Text('Нет'),
                    onPressed: () => Navigator.pop(c, false),
                  ),
                ],
              ),
            ),
        child: ValueListenableBuilder(
          valueListenable: TabNavigator.currentTab,
          builder: (BuildContext context, int value, Widget _) {
            return Scaffold(
              backgroundColor: Colors.white,
              body: IndexedStack(
                index: value,
                children: tabs.map((e) => e.page).toList(),
              ),
              bottomNavigationBar:
                  BlocBuilder<ButtomCubit, bool>(builder: (context, value) {
                if (value == true) {
                  return BottomNavigation(
                    onSelectTab: selectTab,
                    tabs: tabs,
                  );
                }
                if (value == false) {
                  return SizedBox();
                } else {
                  return Container();
                }
              }),
            );
          },
        ));
  }
}