Created attachment 133545 [details]
Yakuake blue bar artedact

SUMMARY

When scrolling console contents, either via mouse wheel or as a result of console output, there appears a thin blue bar on the left of the console contents. The bar height is consistent with the amount of scrolling you perform. When the scrolling stops, after about 200 ms, this bar becomes darker, but still visible.

STEPS TO REPRODUCE

1. Open Yakuake with an empty console with a command line prompt.
2. Press Enter for some time, so that many empty lines are created and the console can be scrolled.
3. Scroll the console up and down, by the mouse wheel, Shift+PageUp and Shift+PageDown or Shift+Arrow keys.

OBSERVED RESULT

As you are pressing Enter (when that results in scrolling the console contents down) or you are scrolling the console in step 3, there appears a blue bar, between the leftmost character on the console and the Yakuake window frame. When you stop scrolling, the blue bar turns darker, after a small delay.

EXPECTED RESULT

There should be no such artefact.

SOFTWARE/OS VERSIONS

Operating System: Kubuntu 20.10
Yakuake: 20.08.1
KDE Plasma Version: 5.19.5
KDE Frameworks Version: 5.74.0
Qt Version: 5.14.2
Kernel Version: 5.8.0-29-lowlatency
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-4700HQ CPU @ 2.40GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 4600

ADDITIONAL INFORMATION

Global UI scaling is disabled (100%).

This is a regression since Kubuntu 20.04 (Yakuake 19.12.3).