Async method in Play Mode being aborted when calling `new System.Windows.Forms.Form`

6.3.X

As Designed

The issue where asynchronous methods appear to stop executing after opening a System.Windows.Forms window in the Unity Editor is not a bug, but expected behavior caused by a synchronization context conflict. Unity uses a custom UnitySynchronizationContext to ensure async continuations run on the main thread. When a Windows Forms window is shown (e.g., via Form.Show()), it installs its own message loop and synchronization context, which can override Unity's. This prevents Unity from processing async continuations, causing them to appear frozen. https://discussions.unity.com/t/winforms-in-unity/668840/6