I've got some interesting observation and just want to check out if it's normal...
I've just got a 4K display which doubled my previously used Full HD resolution. When I launched DO with the new display attached I couldn't read a thing as fonts were super-tiny. When entered preferences, it turned out that virtually all fonts were set at 6 pt! After I've changed them into 9/10 pt it all works perfectly.
However - I doubt the standard font size for DO is 6pt, so I guess I must have had 9 or 10 pt fonts set previously. Can DO actually change fonts by itself?
We'll be improving the way Opus handles DPI changes (and high DPI generally) in the future to make things more seamless and automatic.
At the moment, some config changes may be required to move a config made for one DPI into another DPI.
Going to Preferences / Display / Colors and Fonts and using File > Reset Page to Defaults is the quickest way, if you don't mind the colors also being reset. Otherwise, just go through the list of fonts in the bottom section.
Toolbar font sizes can be changed via Settings > Customize Toolbars.
