Bug 490057

SUMMARY
Enabling "Additionally include mouse buttons" under "System settings - Application permissions - Legacy X11 App Support" results in X11 apps receinving the clicks and gaining focus unintentionally after virtual desktop switching.

STEPS TO REPRODUCE
1. Open an X11 app, I experience this with Google Chrome and Discord.
2. Open System settings and check the "Additionally include mouse buttons".
3. Switch to a different virtual desktop.
4. Use mouse to interact with another X11 app window there, can be window of the same app. Any mouse events sent to X11 window seem to work including mouse move and scrolling.
5. Go back to previous desktop using keybaord shortcuts, I used Meta+Ctrl+Left. It seems important that the cursor is positioned such that it lands on top of a wayland window after virtual desktop switch. Making sure the cursor is also within X11 window bounds seems to help reproduce more reliably.
6. Without moving the cursor away from Wayland window, click in the Setting or or some other wayland app window again.

OBSERVED RESULT
The click drops right through into the X11 app, the X11 app becomes focused on top of wayland app.


EXPECTED RESULT
The click does not go through the same way it did not go through before the virtual desktop switching.


SOFTWARE/OS VERSIONS
KDE Plasma Version: 6.1.2
KDE Frameworks Version: 6.3.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION
With focus stealing prevention is set to "High", the X11 app would still get the click although it would not gain focus.