Hi, I am new to this group. Having been fighting with many issues around a multi-monitor setup in Kubuntu/Neon, I have fixed all problems but one in Kubuntu (my main installed system). Here is the scenario:

|mon1| - |mon2| - |mon3|

Mon1 is 17" 1280x1024 rotated to portrait.
Mon2 is 27" 1920x1080 in landscape.
Mon3 is 17" 1280x1024 rotated to portrait.

It all fits together physically very neatly. Mon1 is to be used for "control & monitoring" with a panel and widgets - it is never used for applications other than Dragon Player and Audacious. Mon2 and mon3 have no panel and no widgets as most often they will be used with full screen or maximized apps like Davinci resolve and the more real estate I can give them, the better. After fixing SDDM this is now working as expected with one exception:

In Neon, clicking on an icon in the panel on the right screen does what you would expect. Open the app wherever it was last opened, does not matter which physical display it is on. This is good.

Kubuntu on the other hand does not do this. It does two things very oddly.

1: it will only open on the display on which you clicked the launcher. This results in needing a panel on every display.

2: If you open KDE apps (specifically) on mon1 they get trapped there and will, after that, only launch there regardless of which panel or display they are launched from. This gets annoying fast.

Non KDE apps do not have this behavior with the exception of Firefox. As Neon does not share this behaviour, it is obviously something within Kubuntu and specific to its tweaks in KDE, ether by design (which I think is the case as Gnome in Ubuntu has the same problem), or by fault.

This is bad. It makes my workflow impossible. It becomes a kludgy mess of toolbars and panels.

Does anybody know how to make Kubuntu act like neon? I have spent too much time tweaking and customizing Kubuntu and really do not want to start over with Neon. The behavior is Kubuntu - I have verified it with both Kubuntu 22.04 and 22.10, and in Ubuntu 22.10.