I don't know if this is a bug in Partition Manager itself, but it is the only app that does this AFAIK. When started from a terminal, it uses ~/.config/partitionmanagerrc. When started from a .desktop file (app menu, krunner, etc.), it uses /root/.config/partitionmanagerrc. It also doesn't use my KDE theme when started this way, which I'd assume is related.
I am not sure if different theme is related to that... sudo does not pass environmental variables, so if you use sudo that is the most common reason for different theme. But maybe you need to set your root user theme to breeze too... KDE Partition Manager 3.0 will help with sudo a bit, it will pass required environmental variables to kdesu in case it uses sudo as a backend. Most likely this is distro issue. I don't reproduce this behaviour on gentoo. It always uses /root/.config/partitionmanagerrc Maybe try to talk to Arch people, also wait and see how 3.0 will change things (should be released tomorrow). If those two options don't work, please reopen this bug.
I fixed the theme issue by copying kdeglobals from ~/.config to /root/.config. Regarding partitionmanagerrc: If I dont use sudo, it opens kdesu. On Arch, it uses ~/.config/partitionmanagerrc (owned by root). On Neon it uses /root/.config/partitionmanagerrc. Either way it runs as root. The Arch package maintainer and I would like confirmation on what the intended behavior is. Is it always supposed to use root's config even if it's launched from the terminal without sudo?
Well, I wouldn't recommend running it manually (except for testing) with "sudo partitionmanager" precisely because it can rerun itself using kdesu and pass required environmental variables (sudo eats them). As for the config file, we obviously want it to be consistent. So whichever way is easier. But I guess /root/.config might be easier since this is how it works in all other distros. I'm actually not sure what Arch does to make it use ~/.config/. Is it some environmental variable?
> I'm actually not sure what Arch does to make it use ~/.config/. Is it some environmental variable? I have no idea, hoping the package maintainer can figure it out. Here's a link: https://bugs.archlinux.org/task/52204
For version 3.1 I think I'll also pass $HOME environmental variable to keep user home dir and theming. Then config will be stored in ~/.config/