The issue is specific to nautilus (as far as I've seen). It usually returns after a session restart (killing and relaunching nautilus fixes the issue). I've attached a before and after image to illustrate the issue, with gedit providing a control to show the 1.75 DPI scaling setting.
** Attachment added: "Nautilus without correct scaling" https://bugs.launchpad.net/ubuntu/+source/nautilus/+bug/1515767/+attachment/4520842/+files/nautilus-no-scaling.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1515767 Title: Nautilus does not follow HIDPI setting To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nautilus/+bug/1515767/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
