UI leaves ghosting artifacts when another window hovers over Flutter app on IGEL OS

### Steps to reproduce

1. Create a basic Flutter counter app:
flutter create counter_app
cd counter_app
2. Run the app on IGEL OS:

flutter run -d linux
3. Open any other terminal window (or any other application window).
4. Hover/drag the terminal window over the Flutter app window and keep it stationary on top of the Flutter app for 5–6 seconds continuously.
5. Move the terminal window away from the Flutter app.

### Expected results

The Flutter app UI should render normally with no visual artifacts after the overlapping window is moved away. The area previously covered by the terminal should redraw cleanly.

### Actual results

The Flutter app UI is distorted — the area where the terminal hovered leaves a visible "mark" or ghosting artifact on the Flutter window. The UI does not redraw correctly and the distortion persists until the window is resized, refocused, or otherwise forced to repaint.

### Code sample

Default flutter create counter app — no modifications needed to reproduce.

### Screenshots or Video

Screenshots / Video demonstration

[Upload media

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### Logs

Logs

```Flutter (Channel stable, 3.41.6, on macOS 26.4.1 25E253 darwin-arm64, locale en-IN) [2.4s]
• Flutter version 3.41.6 on channel stable at /Users/shivam.piyush/Work/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision db50e20168 (5 weeks ago), 2026-03-25 16:21:00 -0700
• Engine revision 425cfb54d0
• Dart version 3.11.4
• DevTools version 2.54.2
• Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop,
enable-android, enable-ios, cli-animations, enable-native-assets, omit-legacy-version-file,
enable-lldb-debugging, enable-uiscene-migration
```

### Flutter Doctor output

Doctor output

```console

Flutter (Channel stable, 3.41.6, on macOS 26.4.1 25E253 darwin-arm64, locale en-IN) [2.4s]
• Flutter version 3.41.6 on channel stable at /Users/shivam.piyush/Work/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision db50e20168 (5 weeks ago), 2026-03-25 16:21:00 -0700
• Engine revision 425cfb54d0
• Dart version 3.11.4
• DevTools version 2.54.2
• Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop,
enable-android, enable-ios, cli-animations, enable-native-assets, omit-legacy-version-file,
enable-lldb-debugging, enable-uiscene-migration

```