Created attachment 151504 [details]
The checkbox I'm referring to

SUMMARY
The widget used for the "primary" setting is a checkbox, which suggests that the feature can be enabled/disabled.
In actual fact, the user is not allowed to uncheck the checkbox. Instead they must click on another screen and check the checkbox from there.
I think it should be clearer that this checkbox is one-way.

Maybe it should be greyed out when it is enabled?
Or maybe it should be replaced with a button. The label in the left column could be "Is primary:" and the text on the right could say "Yes" or "No". If it says "No", then there will also be a button next to it saying "Set screen as primary".

STEPS TO REPRODUCE
1. Have at least two monitors connected
2. Open Display Configuration
3. Click on the primary screen
4. Try to disable the "Primary" checkbox

OBSERVED RESULT
It doesn't work

EXPECTED RESULT
I would expect the checkbox to be unchecked.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20220821
KDE Plasma Version: 5.25.4
KDE Frameworks Version: 5.97.0
Qt Version: 5.15.5
Kernel Version: 5.19.2-1-default (64-bit)
Graphics Platform: X11

ADDITIONAL INFORMATION