Created attachment 82150 [details] Crash backtrace After opening the Activity Manager from the taskbar and selecting "Add Widgets," the bar shows either garbled text or nothing, the taskbar freezes, and then plasma-desktop crashes completely. It will usually reset itself, though sometimes has to be manually reset.
It turns out that the age old solution of turning it off and on again fixed the problem, though I'm sure it would still be useful to find out what caused the problem in the first place.
*** This bug has been marked as a duplicate of bug 302931 ***