SUMMARY On a dual monitor setup (laptop screen plus external monitor) when a monitor is selected as the main monitor it treats the other one as main one. For example if I select external monitor as main the taskbar and notifications appear on the laptop screen and apps default to that one. It works like that both ways. OS: Linux: 6.14.7-arch2-1 (64-bit) KDE Plasma Version: 6.3.5 KDE Frameworks Version: 6.14.0 Qt Version: 6.9.0 ADDITIONAL INFORMATION This stuff happens since some plasma versions, I think it started with version 6.3.2.
The "primary screen" characteristic doesn't determine where the notifications and panels go; it determines where the entire desktop that they live on go. So if you want things to work as you expect, you need to manually move your panel onto the desktop associated with the screen that's *currently* set as the primary screen, and then thereafter changing the primary screen will move them as well.
(In reply to Nate Graham from comment #1) > The "primary screen" characteristic doesn't determine where the > notifications and panels go; it determines where the entire desktop that > they live on go. > > So if you want things to work as you expect, you need to manually move your > panel onto the desktop associated with the screen that's *currently* set as > the primary screen, and then thereafter changing the primary screen will > move them as well. I'm sorry but this sounds like a dumb workaround. Anyway, if you set the notifications position to any place other than "next to notifications icon" it will appear on the primary screen, which is always on the other screen due to this issue. This happens with the taskbar, mouse cursor always appearing on the middle of the other screen and apps that don't have any position set from a previous session defaulting to it. It didn't work like that in any versions prior to 6.3.2
It's not a workaround, it's the way the system was designed to be used. There's even a little contextual info button next to the "Primary Screen" radio button that you can click on which explains what the setting is actually used for. It's been this way for at least 3 years; if something changed in Plasma 6.3.2 for yo, it's possible a bug got fixed that resulted in a prior workaround not working as expected anymore; we're always refining the multi-monitor UX to work in more of an "as designed" manner and less of a "random number generator" manner.