list rendering issue

main.dart

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new SelectScreen(),
    );
  }
}

class SelectScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        body: new Center(
            child: new Container(
      height: 330.0,
      child: new Scrollbar(
          child: new ListView(
              children: new List.generate(10, (int index) {
        return new ListTile(
          title: new Text("$index"),
        );
      }))),
      padding: const EdgeInsets.only(left: 20.0, right: 20.0),
    )));
  }
}