title: Flutter TabBarView expands children
body: <p>In the following code <code>TabBarView</code> expands children <code>LinearProgressIndicator</code> , How can I fix it ?</p>
  <pre class="lang-dart prettyprint-override"><code>import 'package:flutter/material.dart';
  
  void main() {
    runApp(TabBarDemo());
  }
  
  class TabBarDemo extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
        home: DefaultTabController(
          length: 3,
          child: Scaffold(
            appBar: AppBar(
              bottom: TabBar(
                tabs: [
                  Tab(icon: Icon(Icons.directions_car)),
                  Tab(icon: Icon(Icons.directions_transit)),
                  Tab(icon: Icon(Icons.directions_bike)),
                ],
              ),
              title: Text('Tabs Demo'),
            ),
            body: TabBarView(
              children: [
                LinearProgressIndicator(),
                Icon(Icons.directions_transit),
                Icon(Icons.directions_bike),
              ],
            ),
          ),
        ),
      );
    }
  }
  </code></pre>