Firefox display scaling inconsistencies while using Wayland

[Landon R. Brainard]

I have a 2880x1620 onboard display and a 1080p external display that I use for my computer. As far as I can tell xorg does not allow for different scaling options for two separate displays. Based on https://askubuntu.com/questions/1028622/different-display-scale-settings-18-04 I logged in with Wayland and thought I had achieved the effect I wanted. However, after I started using my computer, I realized that some applications were still scaled based on the display I set to be primary. I have my 1080p display set as primary. Firefox, for example, looks just fine on my primary, but when I move it to the higher-DPI display, it does not look correct.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: gdm3 3.32.0-1ubuntu1
ProcVersionSignature: Ubuntu 5.0.0-15.16-generic 5.0.6
Uname: Linux 5.0.0-15-generic x86_64
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat May 25 20:27:34 2019
ExecutablePath: /usr/lib/gdm3/gdm-wayland-session
InstallationDate: Installed on 2019-05-09 (16 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 XDG_RUNTIME_DIR=<set>
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)

[Daniel van Vugt (vanvugt)]

Each graphics toolkit needs to fix this themselves. Unfortunately for Firefox I think it uses its own so it must be fixed separately.

[Daniel van Vugt (vanvugt)]

Also, this sounds like bug 1600053 so let's group it there for now.