Display problems after upgrading to groovy

[advseb]

I'm running Kubuntu in VMware Player on a Windows host. After upgrading to Groovy from 20.04, I noticed graphics problems in KMenu and taskbar. I have open-vm-tools installed and the graphics driver is used.

I tried a fresh Kubuntu 20.10 installation and it has exactly the same problems.

I tried a Ubuntu Budgie 20.10 installation and it doesn't have those problems!

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: plasma-workspace 4:5.19.5-0ubuntu2
ProcVersionSignature: Ubuntu 5.8.0-26.27-generic 5.8.14
Uname: Linux 5.8.0-26-generic x86_64
ApportVersion: 2.20.11-0ubuntu50
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Thu Oct 29 14:51:46 2020
ExecutablePath: /usr/bin/plasmashell
InstallationDate: Installed on 2019-11-03 (361 days ago)
InstallationMedia: Kubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
ProcEnviron:
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/usr/bin/zsh
SourcePackage: plasma-workspace
UpgradeStatus: Upgraded to groovy on 2020-10-25 (3 days ago)

[advseb (adv-seb)]

When hovering the mouse in kmenu over the entries, I see the following messages in ~/.xsession-errors:

file:///usr/share/plasma/plasmoids/org.kde.plasma.kicker/contents/ui/ItemListDialog.qml:51: TypeError: Cannot read property 'separatorCount' of null
trying to show an empty dialog
file:///usr/share/plasma/plasmoids/org.kde.plasma.kicker/contents/ui/ItemListDialog.qml:51: TypeError: Cannot read property 'separatorCount' of null
trying to show an empty dialog

[Marco Parillo (marco-parillo)]

Have you tried disabling 3D acceleration for your guest from the host?

[advseb (adv-seb)]

No, disabling 3D settings in VMware doesn't resolve the problem.

Of course it could also be a regression of the VMware video driver with groovy kernel. Are there any logs I should take a look at to better locate the root cause?

[advseb (adv-seb)]

I close my bug report, because I'm no longer able to reproduce it. In the meantime, there were several Kernel and other updates and maybe one of those updates solved this problem.