I try to handle problems with Linux X-Server with mixed dpi displays.
At the office I would like to use two non HDPI displays, else I like to use the HDPI screen of my XPS13. The best results on the HDPI display I get with changing the dpi settings Xft.dpi
xrdb -merge ~/.Xdefaults
The last remaining problem is that the running applications do not update.
Is there a way to force an update?