SUMMARY The behavior is highly inconsistent and seems to depend on the active desktop while activating the grid effect. Windows always seem to appear on the correct screen but are often on the wrong desktop or completely missing (probably just drawn underneath another window). Here's a video recording that might make the issue easier to understand: https://i.imgur.com/ITw6TQi.mp4 STEPS TO REPRODUCE 1. Attach at least two screens and create a few desktops 2. Place windows on several (if not all) desktops and screens 3. Invoke the grid effect 4. Move to a different desktop and repeat step 3 OBSERVED RESULT Some windows are missing or shown on the wrong desktop, depending on where the effect has been activated from. EXPECTED RESULT Windows should appear consistently on their actual desktop. SOFTWARE/OS VERSIONS Linux: 5.17.13 KDE Plasma Version: 5.25.0 KDE Frameworks Version: 5.94.0 Qt Version: 5.15.2 ADDITIONAL INFORMATION No kwin scripts or windows rules are enabled and this happens under Wayland. Haven't tested on X11 at all.
Just rebooted my machine, without having a second screen attached, and I can still reproduce it. Pretty sure this doesn't happen to everybody as it makes the grid effect pretty much useless. Could there be config left-overs from the previous effect implementation which cause this?
Yep, totally a config left-over from 5.24 as it turned out. Just recently noticed that there was no value chosen in the 'Desktop Grid' effect settings under 'Windows Layout'. As soon as I have chose anything, the effect now behaves properly with both a single and multiple monitors. Not sure if this should be closed as resolved, so I am leaving the bug "CONFIRMED" as it is.