I have the following setup: Laptop monitor 2880x1800 4K monitor 3840x2160 Since plasma6, setting the laptop screen to 125% works almost fine, until you start virtualbox (maybe other apps as well, but vbox is a nice example here) It is sufficient to open the virtualbox main window and change the scale-factor of the laptop screen from 125% to 100% (other values will do as well) Changing scale-values immediately has an effect on the vbox-window size. This would be still fine, but if you start the virtual-machine, then the screen-size (here: windows11) is reported way bigger - depending on the scale factor. This has the effect, that windows thinks it has more pixels for the area covered by the vm-display window resulting in pixelated fonts and way too small ui-elements. You can counter-steer by increasing windows' scale factor as well, but the result is never as clear as if all settings (windows and plasma) are set back to 100% I would consider this a bug... Your thoughts? === Operating System: Fedora Linux 40 KDE Plasma Version: 6.0.4 KDE Frameworks Version: 6.1.0 Qt Version: 6.7.0 Kernel Version: 6.8.8-300.fc40.x86_64 (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 PRO 7840U w/ Radeon 780M Graphics Memory: 58,6 GiB of RAM Graphics Processor: AMD Radeon Graphics Manufacturer: LENOVO Product Name: 21K5000JGE System Version: ThinkPad P14s Gen 4
some more info: i just discovered, that vbox is still X11 (surprise!) I did play with the systemsettings > display config > legacy applications (x11) and modified [ ] 'apply scaling themselves' to [x] 'scaled by the system' Despite the fact that the information-popup says otherwise, this seems to help in the vbox case. Fonts and ui elements are crisp again (regardless of the scaling in windows) independent of plasma scale-factors applied Still annoying, though, because this is a global setting. Can we apply such a behaviour application - wise? (e.g. only for vbox?)
Unfortunately this is systemwide, not per-application. If the app is buggy with "apply scaling themselves", that means it's an app bug, I'm afraid.