SUMMARY Git master everything built against Qt 6.7.2 on Fedora KDE 40. If I Alt+Tab between Breeze-themed windows (e.g. Dolphin and Kate) in such a way that the tabbox UI actually appears, the windows' header areas below the SSD titlebar will fail to switch their color properly. STEPS TO REPRODUCE: 1. Be using the default Breeze Light color scheme 2. Open Kate and Dolphin 3. Focus Kate 4. Hold down Alt 5. Press tab 6. Wait for the tabbox UI to appear 7. Press Tab enough times to go to Dolphin 8. release Alt OBSERVED RESULT Dolphin's toolbar background color isn't the same color as its titlebar EXPECTED RESULT They both match in color
This was caused by https://invent.kde.org/plasma/kwin/-/merge_requests/6160.
The issue is caused by qtwayland synchronizing QWindow::isActive() to the wl_keyboard focus instead of using the xdg_toplevel.activated state. FWIW The same issue can be observed on X11. I'm not sure whether it can be considered as a regression because if the task switcher handled input focus as expected, the behavior would be the same both in the Xorg session and the Wayland session.
s/the behavior would be the same/the behavior would be the same from the get go/
Well, it wasn't happening before that commit and now it is, so I think it counts as a regression. :) It's at least a visual regression. If we ship this, we'll end up with tons of bug reports about it, like Bug 433569, which is similarly minor but highly noticeable.
Appears to be fixed with today's git master!