SUMMARY If focus is given to a program outside of the current virtual desktop, if that program is maximised (or placed too close to a panel on *its* desktop), any floating panel on the *current* desktop will dock to the edge of the screen. STEPS TO REPRODUCE 1. Set up a floating plasma panel 2. Set up at least two virtual desktops 3. Install a program that allows you to give focus to it via a tray icon, such as Slack or Element 4. On virtual desktop 1, start that program and maximise it 5. Go to virtual desktop 2 and make sure it is empty, allowing the panel to float 6. Click the program's tray icon OBSERVED RESULT 7. The desktop is empty, yet the floating plasma panel docks to the edge of the screen for no discernible reason. (The program's icon appears highlighted on task manager widgets calling for attention.) EXPECTED RESULT 7. The plasma panel on the empty desktop remains floating until you switch to the desktop that has actual reason to dock the panel. SOFTWARE/OS VERSIONS Linux/KDE Plasma: EndeavourOS/Arch x86_64 KDE Plasma Version: 6.2.4 KDE Frameworks Version: 6.9.0 Qt Version: 6.8.1 ADDITIONAL INFORMATION I'm running Wayland.
Being able to focus a window on a non-visible virtual desktop itself is the bug; this isn't something that's supposed to happen. The panel de-floating is a curious yet logical side effect of that issue. For what it's worth, I can't reproduce the issue with Discord and it's tray icon in git master. it may already be fixed.
Aha, looks like it was fixed by the commit that fixed Bug 427579, which reported a similar issue. *** This bug has been marked as a duplicate of bug 427579 ***