When I switch the user session, and return back to the now locked old session, I get a garbled lock screen. It almost looks right - just some of the textual characters are missing. For example of the word "Sonntag" (sunday in German), the characters "onn" and "a" are missing. Also the submit button has no text displayed. What is being left out varies. This is with the kubuntu KDE 5.3 backport (because 5.2 plasma was crashing all the time, much more than 5.3 still does), and switching user sessions in 5.2 didn't even work at all... I can provide a screen shot if necessary. Reproducible: Always Steps to Reproduce: 1. KDE menu -> leave -> switch user 2. Switch back to original session with e.g. Ctrl-Alt-F7 3. The old session creates a lock screen that is shown Actual Results: The lock screen is missing characters in the middle of some words Expected Results: The lock screen should show correct words with all characters...
Created attachment 93055 [details] Display of missing characters on lock screen.
The lock screen has nothing to do with kdm. Reassigning to the correct component. Although this rather looks like a graphics driver issue to me.
unfortunately this is a known issue in Qt in relation with the driver. [1], [2] I'm sorry there is not much we can do about it. [1] https://bugreports.qt.io/browse/QTBUG-42386 [2] https://bugreports.qt.io/browse/QTBUG-36976