Internal part do not take the whole space properly

I am using Trelis for mesh generation. Just as the screenshot, there is some space not be properly used in this software. But it is full in Debian gnome.

I am using Manjaro KDE. My GPU is Intel UHD Graphics 630. The driver version is 460.32.03. My screen resolution is 2560x1440.

Do anybody have similar issue?

That is Nvidia driver - is this something CUDA? That is the only way I can make a little sense of your topic.

From your comment in the screen size it seems the app is no utilizing fractional scale - and fractional scaling is some which is set in the apps code.