Linux/WSL: native WebView is hidden after first frame because _scheduleFrameVisibilityCheck() collapses it to 0x0

[faezzz92]

I’m seeing a Linux rendering issue with webview_all_linux where the page loads successfully, JavaScript works, and the native GTK/WebKit view is initially given the correct size, but the widget is immediately hidden again.

Environment

• webview_all_linux: 0.5.4
• Flutter: 3.41.6
• Linux target
• Reproduced in WSL/WSLg on Ubuntu
• Web content example: https://flutter.dev/

Actual behavior

• onPageFinished fires
• JavaScript can read the DOM successfully
• GTK allocates the native view with the correct size
• then the plugin sends another frame update with width=0, height=0, visible=false
  result: webview stays blank even though the page is loaded

Expected behavior
Once the native Linux webview has a valid frame and is attached, it should remain visible until:

• its geometry changes
• it is detached
• it is disposed
  It should not be hidden just because the Flutter placeholder did not repaint in the next frame.

Relevant logs

webview_all_linux[1]: setFrame x=0 y=0 w=1280 h=636 visible=1
webview_all_linux[1]: allocated x=0 y=0 w=1280 h=636 visible=1 mapped=1
webview_all_linux[1]: setFrame x=0 y=0 w=0 h=0 visible=0

At the same time, page load still completes:

Finished https://flutter.dev/
DOM state url=https://flutter.dev/ ready=complete title=Flutter - Build apps for any screen bodyLength=3290.0 bg=rgb(255, 255, 255)

So the issue is not page loading; it is the native view being hidden after attach.

Root cause
The problem appears to be in _LinuxPlatformWebViewState inside lib/src/linux_webview_controller.dart.

The _scheduleFrameVisibilityCheck() watchdog hides the native view whenever the Flutter placeholder is not painted in a frame:

if (!_paintedThisFrame && _attached) {
  _pushRect(Rect.zero, visible: false);
}

For mostly static layouts, this is incorrect. The placeholder does not need to repaint every frame for the native webview to remain valid.

Workaround
I locally removed _scheduleFrameVisibilityCheck() and kept visibility updates only from:

• _handlePaint() for geometry changes
• detach() / dispose() for hiding
  After that change, the Linux webview rendered correctly.

Suggested fix
Remove or relax the per-frame visibility watchdog so the native webview is not collapsed to 0x0 just because no Flutter repaint happened in the following frame.

[moluopro]

The issue has been fixed in the latest version.