Flutter bug

import 'package:flutter/material.dart';

void main() {
  return runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DefaultTabController(
        length: 3,
        child: new Scaffold(
          body: TabBarView(
            children: [
              Home(), Second(), Third(),
            ],
          ),
          bottomNavigationBar: new TabBar(
            tabs: [
              Tab(icon: Icon(Icons.home),),
              Tab(icon: Icon(Icons.people),),
              Tab(icon: Icon(Icons.event_note,)),
            ],
            labelColor: Colors.red,
            unselectedLabelColor: Colors.blue,
            indicatorSize: TabBarIndicatorSize.label,
            indicatorPadding: EdgeInsets.all(5.0),
            indicatorColor: Colors.red,
          ),
        ),
      )
    );
  }
}

Navigator ownNavigationContext(Widget Function(BuildContext) callback) {
  return Navigator(
    initialRoute: '/',
    onGenerateRoute: (settings) {
      return MaterialPageRoute(
        builder: callback,
        settings: settings,
      );
    },
  );
}

class Second extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return ownNavigationContext((context) {
      return Center(child: Text("Click on the tabbar icon to the right to reproduce the bug!"));
    });
  }
}

class Third extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Center(child: Text("Click on the tabbar icon to the right to reproduce the bug!"));
  }
}

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Center(child: Text("Click on the tabbar icon to the right to reproduce the bug!"));
  }
}