I confirm #6. First, as I have to do every time I boot into my Ubuntu 17.10 VM under Parallels 13, I went to Settings > Devices > Displays and changed my scaling to 200% so I can actually read text. Then I performed some outstanding Ubuntu software updates and rebooted when prompted. When I logged back in, the scaling controls were no longer present in Settings > Devices > Displays, so now I'm stuck with tiny text and UI.
I suspect the cause of the missing scaling controls was the software update I performed to mutter 3.26.2-0ubuntu0.1, which the changelog says introduced a HiDPI-related patch for bug #1724024. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1720465 Title: HiDPI scaling does not hold across reboot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1720465/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs