[Wayland] Display change "Revert Settings" window uses primary screen scaling factor

Using 19.04 disco with Wayland.

I have a HiDPI laptop screen (XPS13) and a normal DPI external monitor. I have the laptop screen set to 200% and the external screen set to 100%.

If I set the primary display to the built-in display but have the display settings window open on the external screen, then when I change the scaling factor of the built-in display to e.g. 300% and click Apply, the "Do you want to keep these settings" confirmation window appears on the external screen, scaled by 300%. If the external monitor is the primary display, it is always scaled normally at 100%.

Conversely, if the external monitor is set as the primary display, but the settings window is on the built-in display, then when I change the scaling factor of the external monitor to 100%, then this "Do you want to keep these settings" dialog appears incorrectly scaled at 100% instead of 200%.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: gnome-control-center 1:3.32.1-1ubuntu4
ProcVersionSignature: Ubuntu 5.0.0-13.14-generic 5.0.6
Uname: Linux 5.0.0-13-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Apr 26 14:16:23 2019
EcryptfsInUse: Yes
InstallationDate: Installed on 2018-09-04 (234 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
SourcePackage: gnome-control-center
UpgradeStatus: Upgraded to disco on 2019-04-25 (0 days ago)