Created attachment 150952 [details]
Screen recording

STEPS TO REPRODUCE
1.  Open Xournal++ 1.1.1+dev (b5da66c9)
2.  File -> Preferences -> View: "Highlight cursor position", "Radius 30", "Border width: 0", Cursor Icon for Pen "Small dot"
3.  Draw something with your tablet or mouse in Xournal++ using the pen tool

OBSERVED RESULT
Using 200% scaling, the highlighting, which is a bright yellow by default, becomes a dark yellow and every now and then a rectangle appears at the cursor within the highlighting. I could not observe this when changing the scaling to something lower, like 100% or 125%.

Please see the bad screen recording. I had to use my phone since OBS studio did not record the highlighting.

I could not observe this using the nightly Appimage [1]  on Fedora 36 with Gnome 42 Wayland and 200% scaling, corresponding to the same git commit as my local build on TW. So I guess it could be a kWin issue.

Though I could neither trigger it with the stable version of Xournal++ 1.1.1 from the openSUSE TW repo. So maybe a Xournal++ issue after all? 

Hopefully someone can reproduce it.

[1] https://github.com/xournalpp/xournalpp/releases/tag/nightly


SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20220725
KDE Plasma Version: 5.25.3
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5
Kernel Version: 5.18.11-1-default (64-bit)
Graphics Platform: Wayland
Graphics Processor: AMD Radeon RX 580 Series