I'm using Ubuntu 18.04, installed a couple of desktops, but I'm getting this weird behaviour where GTK3 windows, buttons and fonts are either too small or two large. For example, this is a terminal window on my xfce4:
Notice that not all elements are huge, and all fonts are set to 12 or 10. I haven't been able to reach a conclusion what's the cause. I tried removing all my local dotfiles and configs, reset gsettings and dconf, but nothing changed. This weird behaviour happens with the gdm3 as well, where everything is super tiny.