This happens at least once an hour until I kill and restart the plasmashell process. Issue has started in the past week. htop tells me one of my CPUs gets maxed out usage and it makes most of the UI unresponsive.

Trying to right-click for the context menu on any tray icon, or left-clicking to change apps or virtual desktop is extremely unresponsive. Even trying to open the start menu freezes. Swapping virtual desktops using hotkeys is still fast, and actions within any of the apps like KSysGuard, Discord or whatever are all still fast.

Specs and software:
Kubuntu 20.04 LTS
KDE Plasma 5.18.5
KDE Frameworks 5.68
Qt 5.12.8
Dell XPS 13
16GB RAM
i7-8565U

Before filing a bug where it belongs (https://bugs.kde.org) please upgrade your Kubuntu installation and see if that still occurs.

FWIW: you can try narrowing this down by selectively disabling the Desktop Effects that are in use. Please also specify what changes you did to the basic installation in terms of Themes, etc.

I swapped Kubuntu from LTS to normal release cycle to upgrade KDE and this seems to have solved the issue. Thanks!

Hi!

I have encountered a similar problem on my Dell XPS 13 running debian Bullseye with plasmashell version 5.20.5 and X11. In my case the issue is that while working with an application (e.g. inkscape) the whole shell freezes and starts to fully use a CPU core - htop shows, that it is the plasmashell process demanding the CPU resources. Then after a while I manage to restart the shell (with: "kquitapp5 plasmashell || killall plasmashell && kstart5 plasmashell") and system goes back to normal. The .xsession-error logs these lines before the restart:

qt.svg: <input>:413:631: Could not add child element to parent element because the types are incorrect.
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:23:1: Type InputPanel unavailable
qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml:127:5: Type Keyboard unavailable
qrc:/QtQuick/VirtualKeyboard/content/components/Keyboard.qml:38:1: module "QtQuick.VirtualKeyboard.Plugins" is not installed
kf.coreaddons: KDirWatch: "/home/t/.local/share/wallpapers" is a directory. Use addDir!
kf.coreaddons: KDirWatch: "/usr/share/desktop-base/homeworld-theme/wallpaper" is a directory. Use addDir!

I would be thankful for any ideas how to solve the issue or what may trigger the problem.

Thanks in advance.

T.