[Problem/Bug]: Artifacts on transparent windows. (URGENT!)

[eythaann]

What happened?

I had a lot of reports on my app caused by this: eythaann/Seelen-UI#1304
This only start happening since webview2 runtime 144.x.x on version 143.x.x this didn't happen.

Probably the issue is related with #5481 as well it is an issue on transparency.

All webviews will have this old classic title bar, I have worked a lot on windows, so I know that this probably is caused by not handling the WM_NCACTIVATE, WM_NCPAINT and maybe others WM_NC* events.

Importance

Important. My app's user experience is significantly compromised.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

144.0.3719.82

SDK Version

No response

Framework

Win32

Operating System

Windows 11

OS Version

26220.7653

Repro steps

just create a transparent WebView using 144+ webview2 runtime

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

Regression in newer Runtime

Last working version (if regression)

Runtime 143.0.3650.139

AB#60809406

[cryptofyre]

+1, Problematic in production; Needs to be resolved.

[castorix]

Probably the issue is related with #5481 as well it is an issue on transparency.

It seems different, because if I compile the C++/Win32 code I posted to check transparency, it works with 144.0.3719.82 Runtime version (at least on my Windows 10 22H2 OS) and does not work anymore with >= 145.x versions (gray or white background instead of transparent background) :

[SamarthMP]

Bump, causing issues for me as well.

[golok727]

+1