Bug 492483

SUMMARY
"Leave" screen improperly shown on built-in screen, when using multiple monitors in Extend layout

STEPS TO REPRODUCE
1. Use a 2-monitor setup with a laptop and an external screen, in an "Extend" layout
2. Press Ctrl+Alt+Del to show what I would call the "Leave" screen (not sure about the official name)
3. Use Tab or Shift+Tab to navigate through the options (Log Out, Shut Down, etc.)

OBSERVED RESULT
The currently selected option is only highlighted on the external monitor, not on the laptop's built-in monitor. This is very confusing to me: if I happen to be looking at the built-in monitor when I'm pressing Ctrl+Alt+Del, my first thought is that I can use that monitor to control what I'm doing, since the options are displayed on that monitor; but I have to remember every time "oh true, there's a bug, so I have to look at the other monitor". It would actually already be better to not display anything on the built-in monitor, rather than displaying an incorrect screen - I would then come faster to the realization that I shouldn't look at that monitor. I guess I'll get used to that behavior with time, but for now it's tiring.

EXPECTED RESULT
Ideally, I would expect the display to be perfectly mirrored when the "Leave" screen kicks in. That would also play more nicely with using the mouse: no need to think about which monitor the mouse pointer is currently on.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Debian 12
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
I'm not sure whether I should file a separate ticket for this (and this is arguably more of a design debate than a bug), but I also find it a bit strange that if I start using the mouse for hovering over options (Log Out, etc.), the option currently selected with the keyboard (or Log Out by default, if the keyboard hasn't been used) remains highlighted while I hover over other options.