This is not common windows paradigm but it’s how unity engine has worked for over a decade on Windows and Linux and it should be consistent on all 3 OS.

*Repro:*
# Create a new 3D project
# Click Window > Search > New Window
# Click on anywhere in the Main Unity Editor window

*Expected result:* Floating window stays on top of the Main Unity Editor window
*Actual result:* Floating window is hidden behind the Main Unity Editor window

*Notes:*
* When Editor is in Fullscreen, floating windows do not get sent to the back.
* When Editor is in Zoom, floating windows are sent to the back.
* Upon opening a window in Fullscreen and then returning to Zoom, the floating window now does not get sent to the back.

Floating window behaviors should be standardized, as inconsistencies disrupt certain workflows and user experience.