Expected Behaviour of windows appearing when app is full-screened

Hi folks,

Got a question on the behaviour of apps when they are in full screen mode, and moreso, when another app tries to show itself.

For example,

if app A is open and in fullscreen mode, I cannot drag a window from app B (that is not in full screen mode) on top of it.

However, I can drag another window from app A (that is not in full screen mode) on top of it.

With that said, programtically, I can open a window from app B on top of app A (despite app A being full screened).

Is there documentation on the specific rules with regards to an app in full screen, and similarly, an app in tiled full screen (ie split full screened).

Trying to understand if the programatic opening of app B window on top of app A (fullscreened) is expected, or a bug, given that manually dragging isn't allowed.

Thanks!

Expected Behaviour of windows appearing when app is full-screened
 
 
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