Fullscreen is always on monitor 1, instead of the monitor where the Shotwell window is
My monitors configuration looks like this, with monitor no1 being on the left but secondary, and monitor no2 being on the right but primary (where the GNOME Shell top bar appears):
Testing on the GNOME 45 Wayland session, fullscreening Shotwell when viewing images in the library results in Shotwell always fullscreening on monitor no1, even if the Shotwell window was on monitor no2. Other image viewers (gthumb, loupe, EOG, etc.) have no trouble fullscreening onto the monitor where their window is located at any given time.
At first, I thought maybe this is a Wayland-specific thing, but this was originally reported by @adamd in #1197 (closed) in 2010, way before Wayland:
If I have multiple monitors and I put Shotwell into fullscreen mode, it should go fullscreen on the monitor where its window is presently located, just like other GNOME applications. But on my laptop, Shotwell goes fullscreen on the external monitor even when the Shotwell window was on the laptop display.
Either the issue got erronously auto-closed, or the issue was fixed at some point and then reappeared in recent years...