After updating my qubes installation, my fedora-26 acts up, with huge icons, possibly due to the extreme resolution of my Lenovo Yoga Pro 2.
To fix this install gnome-tweak-tool, and resize fonts and windows to something else and return back again. That will fix it.
First installation with huge fonts:
Select quit and you’re done.
Looking beautiful again:
Fedora-27 didn’t have this problem, but is slow as hell compared to fedora-26, so guessing tweaking is required.