kubuntu panel freezes on return from lockscreen

[Peter Hewett]

By default, Kubuntu automatically locks the screen. Password is needed to reopen the desktop. Sometimes, the panel at the bottom of the screen is frozen. Apps perform normally, but starting and stopping apps don't change what is shown on the panel. The clock on the panel stays frozen at the time the screen locked.
Application identified by xprop WM_CLASS is plasmashell, but launchpad does not accept this as a package.

[Peter Hewett (peter-hewett)]

This is a fresh install of Kubuntu 17.10 64bit. No widgets added to panel.
6 apps are pinned to the panel (konsole, thunderbird, firefox, dolphin, chromium, cantata).

When the panel is frozen, the pinned apps still start when I click on their icon, and the application launcher works ok. Just the task manager section showing running apps is frozen, and the clock is stopped.

Log out and log in clears the problem (until next time screen locks). Sometime, the panel works ok after screen lock, sometimes it freezes.

[Peter Hewett (peter-hewett)]

All 6 apps removed from panel, but still have the same symptoms.
Other than those, no widgets were added to the default Kubuntu 17.10 install (apart from setting 4 virtual desktops).

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Peter Hewett (peter-hewett)]

A few days ago, I turned off screen locking (in system settings > desktop behaviour) and the problem hasn't happened since then.

[Prophet (prophet005)]

I have exactly the same issue when I come back to the Desktop after playing a game in fullscreen mode.

[Scarlett Gately Moore (scarlettmoore)]

THis bug is very old, if it remains an issue please update the bug with info from a supported release.

[Launchpad Janitor (janitor)]

[Expired for plasma-workspace (Ubuntu) because there has been no activity for 60 days.]