KDE Plasma - bizarre issue with invisible applications

Hello,

I’m experiencing a very bizarre issue occuring only in KDE Plasma environment.
I have installed KDE using the steps outlined here: Installing KDE? Everything downloads but stays cached? - #4 by necker
And everything seemed to be working fine until I have restarted my machine.

So, what I have now is when I try to launch any non dom0 application, all I get is a loading indicator (next to my cursor) that shows up for a few seconds and then disappears (and the application window is not visible anywhere: its main window on the desktop, its title in the panel, etc), so it looks as if I haven’t lauched that application or haven’t even clicked on its shortcut in the menu.

However, if I log out and log in to the XFCE, I can see that application I tried to launch, running fine (its window) and it’s normally visible.

I have no clue what could be the cause as after the first log in to the KDE Plasma all I did, was just tweaked a few settings related to desktop effects. I tried to reset all desktop effect settings back to the default, also tried reinstalling the Qubes OS entirely but it didn’t help.

Btw, I’m using the 4.1.0-rc4 version, just noticed that the stable version was just released, will try to upgrade and see if it helps…

Could you please help me resolve this? Thanks.

I do experience the exact same behavior!

A logout/login fixes this. Sometimes.

There are 2 errrors from plasmashell when launchin qubes succesfully:

kf.plasma.core: findInCache with a lastModified timestamp of 0 is deprecated

and

qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 2586, resource id: 37749080, major code: 15 (QueryTree), minor code: 0

I am not 100% sure, but i think this error only appears when the launched windows are invisible.

org.kde.plasma.notifications: Notification from service ":1.38" didn't contain any identification information, this is an application bug!

btw: I do get the notifications (qube starting, qube started).

Maybe somebody can make sense of it, or help by finding more information on what it causes.