When disconnecting external display, XRG ends up outside of screen

[hmijail]

I put XRG's window in the corner of an external display (located up and left from the MacBook's display, in case that matters).
When that display is disconnected, XRG is still running and its window shows in Mission Control, but otherwise it is invisible. The Mission Control animation seems to show it coming from the top.

[hmijail]

Restarting XRG makes it appear again in the currently available display.

[hmijail]

Still an issue in XRG 3.1, macOS 12.1.