I've a laptop with a HiDPI display, running Linux Mint KDE 18 KDE edition (plasma 5.6.5, kde frameworks 5.23.0, qt 5.5.1). I've got KDE configured so it looks good on the display after a very quick google, and all the KDE apps, firefox, chrome, etc, look fine.

The issue I have is that one app I need to use for work, Citrix Receiver, displays everything far too small. I can't play with settings on the Citrix server side, and extensive searching hasn't revealed anything I can do to configure the client on my laptop to resolve this. I can see the same issue with other apps too, for example xterm, so it's not an issue just related to Citrix Receiver.

I've spent a while looking if there is something I can do on a per-application basis, but couldn't find anything (though apparently Gnome can use the environment variable GDK_DPI_SCALE, no use to me of course). The only thing I can think of is running a VM in Virtualbox and scaling the vbox output just in order to run Citrix Receiver, is there anything else worth trying?

Thanks

change your resolution? (see settings>displays). This would be painful but maybe you could start a second X session on e.g. tty6? dont know about kde activities, maybe worth a look.