TextField onTap behavior with different routes

textfield-ontap.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: Center(
            child: Container(
                child: TextField(
          decoration: InputDecoration(
              suffixIcon: Container(
                  padding: EdgeInsets.symmetric(vertical: 10),
                  child: FloatingActionButton(
                    child: Icon(Icons.add),
                    onPressed: () {
                      Navigator.push(context,
                          MaterialPageRoute(builder: (context) => PageB()));
                    },
                  ))),
          onTap: () {
            Navigator.push(
                context, MaterialPageRoute(builder: (context) => PageC()));
          },
        ))));
  }
}

class PageB extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Page B'),
      ),
    );
  }
}

class PageC extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Page C'),
      ),
    );
  }
}

flutter/flutter#45890