Image size with display scaling

Running DO 12.27 on Windows 11 x64 build 22000.675. I have two 80cm monitors, one with a resolution of 2560x1600, the other a 4k 3840x2160 monitor. The lower res monitor has UI scaling set to 100% and the 4k monitor set to 150%, so that UI text and other elements are approximately the same size on both monitors, and this works fine. The problem I have is that, when the DO image viewer is positioned on the 4k monitor, and I open a 4k image and select View / View Size / Original Size off the menu, it actually shows the image at 150%, though the status bar at the bottom of the window indicates 100%.

If I open the same image in Photoshop on the 4k monitor, and tell Photoshop to scale it at 100%, then it displays correctly at 100%, ignoring the UI scaling setting of the monitor, so it's obviously possible for this to be done.

Scaling is based on the primary monitor. Everything is rendered at that monitor’s DPI and then scaled if displayed on a monitor with different DPI.

For best results, make the 4K monitor the primary one, then use File > Exit Directory Opus to restart Opus. (Or reboot to be sure. There are still some things in the OS that don’t update for DPI changes until a reboot.)

(Mixed DPI is also best avoided in general as it causes a lot of problems in Windows itself.)