Flutter window_manager teardown issue

main-broken.dart

import 'package:flutter/material.dart';
import 'package:window_manager/window_manager.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await windowManager.ensureInitialized();
  WindowOptions windowOptions = WindowOptions(
    size: Size(1280, 720),
    minimumSize: Size(640, 480),
    center: false,
    backgroundColor: Colors.transparent,
    skipTaskbar: false,
    titleBarStyle: TitleBarStyle.normal,
  );
  windowManager.waitUntilReadyToShow(windowOptions, () async {
    await windowManager.show();
    await windowManager.focus();
    windowManager.setPreventClose(true);
    _CustomWindowListener _wmListener = _CustomWindowListener();
    _wmListener.setup();
  });

  runApp(const MyApp());
}

class _CustomWindowListener extends WindowListener {
  void setup() {
    windowManager.addListener(this);
  }

  @override
  void onWindowClose() {
    windowManager.destroy();
  }
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() => _counter++);
  }

  @override
  Widget build(BuildContext context) {
    //
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text('You have pushed the button this many times:'),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}

main-ok.dart

import 'package:flutter/material.dart';
import 'package:window_manager/window_manager.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await windowManager.ensureInitialized();
  WindowOptions windowOptions = WindowOptions(
    size: Size(1280, 720),
    minimumSize: Size(640, 480),
    center: false,
    backgroundColor: Colors.transparent,
    skipTaskbar: false,
    titleBarStyle: TitleBarStyle.normal,
  );
  windowManager.waitUntilReadyToShow(windowOptions, () async {
    await windowManager.show();
    await windowManager.focus();
    windowManager.setPreventClose(true);
    _CustomWindowListener _wmListener = _CustomWindowListener();
    _wmListener.setup();
  });

  runApp(const MyApp());
}

class _CustomWindowListener extends WindowListener {
  void setup() {
    windowManager.addListener(this);
  }

  @override
  void onWindowClose() {
    windowManager.setPreventClose(false);
    windowManager.close();
  }
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() => _counter++);
  }

  @override
  Widget build(BuildContext context) {
    //
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text('You have pushed the button this many times:'),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}