Created attachment 156427 [details] screencast of the bug SUMMARY A flashing vertical white line appears under KRunner, when the match list shrinks. STEPS TO REPRODUCE 1. On desktop, press 'k' to bring up KRrunner. 2. Press backspace. OBSERVED RESULT A flashing vertical white line appears under KRunner (see 1st attachment) EXPECTED RESULT Nothing. SOFTWARE/OS VERSIONS Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.27.0 KDE Frameworks Version: 5.103.0 Qt Version: 5.15.8 ADDITIONAL INFORMATION Wayland. 250% zoom. I enabled the Show Paint effect (2nd attachment). You can see that after the match list shrinks, its original area is still repainted every second. That might be related. (Screen capture softwares (Kooha and OBS) somehow won't capture KRunner, so I used my phone to record.)
Created attachment 156428 [details] Show Paint
Same root cause as Bug 464526, which is fixed in Plasma 5.27.1. *** This bug has been marked as a duplicate of bug 464526 ***
Disabling Background Contrast doesn't fix the problem for me. So perhaps this is a separate issue than https://bugs.kde.org/show_bug.cgi?id=464526.
Ah then it must be Bug 465158. These bugs all seem to be one or the other; they're quite similar. *** This bug has been marked as a duplicate of bug 465158 ***
(In reply to Nate Graham from comment #4) > Ah then it must be Bug 465158. These bugs all seem to be one or the other; > they're quite similar. > > *** This bug has been marked as a duplicate of bug 465158 *** I upgraded to 5.27.1 and turned off both Blur and Background Contrast, as in bug 465158, then the problem disappeared. So I think you are right.