Problem with AltGr key in flutter Windows desktop - flutter

Question

In any Flutter app in a TextField widget, on Windows, pressing once the AltGr key will drive Windows keyboard crazy: after pressing AltGr, Windows behaves as if the ctrl key was pressed continuously in any application. (Pressing a simple v behaves like if the ctrl-v was pressed) Just double-pressing the left ctrl key will stop this strange state.
Thus, no Windows application written in flutter can be published because if the user presses the AltGr key, he will not understand why his keyboard will not work in any other application afterwards.
It can be reproduced every time, in every environment. On other Windows too. On other machine too. In release exe version too. E.g. in StaleFulWidget, and a TextField in it.
Could somebody help me to solve this very serious Flutter bug? Thank you in advance.
Windows version: Win 10 Pro 20H2 (build:19042.870) Hungarian version. In Hungarian keyboard the # key is AltGr+v. So users can not type any email address.
Flutter versions:
Flutter is already up to date on channel beta
Flutter 2.1.0-12.2.pre • channel beta • https://github.com/flutter/flutter.git
Framework • revision 5bedb7b1d5 (6 days ago) • 2021-03-17 17:06:30 -0700
Engine • revision 711ab3fda0
Tools • Dart 2.13.0 (build 2.13.0-116.0.dev)
Flutter doctor is perfect.
C:\flutter\bin\flutter.bat doctor --verbose
[√] Flutter (Channel beta, 2.1.0-12.2.pre, on Microsoft Windows [Version 10.0.19042.870], locale hu-HU)
• Flutter version 2.1.0-12.2.pre at C:\flutter
• Framework revision 5bedb7b1d5 (6 days ago), 2021-03-17 17:06:30 -0700
• Engine revision 711ab3fda0
• Dart version 2.13.0 (build 2.13.0-116.0.dev)
[√] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
• Android SDK at C:\Users\zsmik\AppData\Local\Android\sdk
• Platform android-30, build-tools 30.0.3
• Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
• All Android licenses accepted.
[√] Chrome - develop for the web
• Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe
[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.9.2)
• Visual Studio at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community
• Visual Studio Community 2019 version 16.9.31112.23
• Windows 10 SDK version 10.0.18362.0
[√] Android Studio (version 4.1.0)
• Android Studio at C:\Program Files\Android\Android Studio
• Flutter plugin can be installed from:
https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
[√] Connected device (3 available)
• Windows (desktop) • windows • windows-x64 • Microsoft Windows [Version 10.0.19042.870]
• Chrome (web) • chrome • web-javascript • Google Chrome 89.0.4389.90
• Edge (web) • edge • web-javascript • Microsoft Edge 89.0.774.57
• No issues found!

Answer 1

As of December 6 2021, this is fixed on the master channel.
If you don't want other projects to be affected, you can use https://pub.dev/packages/fvm to use that channel on a per-project level:
activate the tool, running dart pub global activate fvm in your project directory
run fvm use master
run your app using fvm flutter run, or specify the flutter SDK symlinked in your project folder within the ".fvm" directory for your IDE to use for compiling the app.