It seems this change broke scrollbar theming in non-Adwaita themes. Reverting the change restores the functionality.
There might be other UI elements similarly affected.
You should be able to reproduce with any theme, but for reference, I am using this one: https://github.com/RocketMan/Solaris-11
Created attachment 433931 [details]
Screenshot: scrollbar after r280077
Created attachment 433932 [details]
Screenshot: Expected scrollbar with change reverted
Created attachment 433933 [details]
Note that as soon as we migrate to GTK4 the theme won't be used anyway - there's no way to foreign draw scrollbars. In fact, for 41 we'll likely default to custom drawn scrollbars at least for Adwaita, so that we can use dark scrollbars when possible - another thing not possible with themes. For now though it was just a typo.
(In reply to Alexander Mikhaylenko from comment #3)
> Created attachment 433933 [details]
This has to be the fastest fix ever. Thank you! I am building now to validate.
Confirmed, the patch resolves the issue for me. Thanks again.
Committed r280140 (239841@main): <https://commits.webkit.org/239841@main>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 433933 [details].