[dbm5]

Not sure if it is worth it for your use case, but I was successful in creating a virtual display - second screen - and putting the window there. That did work. I was trying to get kb input and mouse clicks to work, but then realized that that was even more useless than spinning a window to begin with (lol) so backed out all that effort for this much simpler implementation.

EDIT: private APIs — CGVirtualDisplay / CGVirtualDisplayDescriptor / │ CGVirtualDisplayMode (the same ones BetterDisplay uses)

[mortenjorck]

Oh, that's pretty clever! Create a dummy display that never actually renders anywhere and use it as the holding area for "temporarily hidden" windows.

Does the dummy display have to live within the desktop geometry (as in the user could accidentally move the cursor off one edge onto it) or can it be totally isolated?