Steps to reproduce by spamming right click during drag (one of two ways to see bug appear):
- try to drag a widget with the left button but also tapping the right mouse button at the same time If the drag works as expected, reattempt the same drag until it the freeze happens, typically within about 10-20 attempts
- When the widget freezes, and it’s in debug mode, an assert gets printed that comes from the flutter engine and gets printed in the console (see assert exception thrown below)
Here is exception that throws in the flutter/dart engine:
logs
Error: Assertion failed: org-dartlang-sdk:///flutter_web_sdk/lib/_engine/engine/pointer_converter.dart:449:18
state.down
is not true
at Object.throw_ [as throw] (http://localhost:59758/dart_sdk.js:5330:11)
at Object.assertFailed (http://localhost:59758/dart_sdk.js:5266:15)
at _engine.PointerDataConverter.new.convert (http://localhost:59758/dart_sdk.js:165537:46)
at _engine._PointerAdapter.new.[_convertEventsToPointerData] (http://localhost:59758/dart_sdk.js:164956:36)
at http://localhost:59758/dart_sdk.js:164891:44
at http://localhost:59758/dart_sdk.js:164860:16
at http://localhost:59758/dart_sdk.js:164559:11
Error: Assertion failed: org-dartlang-sdk:///flutter_web_sdk/lib/_engine/engine/pointer_converter.dart:449:18
state.down
is not true
at Object.throw_ [as throw] (http://localhost:59758/dart_sdk.js:5330:11)
at Object.assertFailed (http://localhost:59758/dart_sdk.js:5266:15)
at _engine.PointerDataConverter.new.convert (http://localhost:59758/dart_sdk.js:165537:46)
at _engine._PointerAdapter.new.[_convertEventsToPointerData] (http://localhost:59758/dart_sdk.js:164956:36)
at http://localhost:59758/dart_sdk.js:164891:44
at http://localhost:59758/dart_sdk.js:164860:16
at http://localhost:59758/dart_sdk.js:164559:11
Error: Assertion failed: org-dartlang-sdk:///flutter_web_sdk/lib/_engine/engine/pointer_converter.dart:484:18
state.down
is not true
at Object.throw_ [as throw] (http://localhost:59758/dart_sdk.js:5330:11)
at Object.assertFailed (http://localhost:59758/dart_sdk.js:5266:15)
flutter doctor -v
[✓] Flutter (Channel master, 1.26.0-13.0.pre.156, on macOS 11.1 20C69
darwin-x64, locale en-US)
• Flutter version 1.26.0-13.0.pre.156 at
/Users/halvorsen/Development/flutter
• Framework revision 92427f260a (6 days ago), 2021-01-25 12:29:05 -0800
• Engine revision 05b4bec8b3
• Dart version 2.12.0 (build 2.12.0-253.0.dev)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
• Android SDK at /Users/halvorsen/Library/Android/sdk
• Platform android-30, build-tools 30.0.3
• Java binary at: /Applications/Android
Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build
1.8.0_242-release-1644-b3-6915495)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 12.4, Build version 12D4e
• CocoaPods version 1.10.1
[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Android Studio (version 4.1)
• Android Studio at /Applications/Android Studio.app/Contents
• 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-b3-6915495)
[✓] VS Code (version 1.52.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.19.0
[✓] Connected device (1 available)
• Chrome (web) • chrome • web-javascript • Google Chrome 88.0.4324.96
Steps to reproduce by spamming right click during drag (one of two ways to see bug appear):
- try to drag a widget with the left button but also tapping the right mouse button at the same time If the drag works as expected, reattempt the same drag until it the freeze happens, typically within about 10-20 attempts
- When the widget freezes, and it’s in debug mode, an assert gets printed that comes from the flutter engine and gets printed in the console (see assert exception thrown below)
Here is exception that throws in the flutter/dart engine:
logs
flutter doctor -v