Recently I started having graphics glitches with JDownloader on Linux. I've been using JDownloader for years now and I love it. I'm not sure what changed.

I have attached screen capture images of what the graphical errors look like. The only things I have done is remove any identifiable information by painting with bright red color. The rest of the image is exactly as it appears on my system.

My system specs:

Operating System: Kubuntu 19.04
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.56.0
Qt Version: 5.12.2
Kernel Version: 5.0.0-13-generic
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-3570K CPU @ 3.40GHz
Memory: 15.5 GiB of RAM
Nvidia Driver version: 418.56

I have 4k dual-monitor displays using Nvidia. I think this version of Ubuntu is using Wayland by default, but I am not sure that matters.

Troubleshooting so far:

I have downloaded a fresh copy of JDownloader and installed it cleanly. The error results were the same.

I have tested using Nvidia and open-source Nouveau provided drivers (full reboots) but it made not difference with the graphics redraw errors. There is nothing like JDownloader and I would really love to continue using it. Any help would be appreciated.

The only Setting change I made to JDownloader was LAFSettings: Font Scale Factor set to 200 (just so I can read the text on my big 4k monitor display). But the errors occur if I return it to the default 100. I'm only listing that in case it is relevant. The graphical errors still happen even on default fresh installs of JDownloader.

Please help.

[Jiaz]

What java version are you using?
Check about dialog of JDownloader.
Most likely this is caused by compatibility issues between java and your window manager.