Linux(X11): Application quits prematurely before Power Off

[torum]

Let's say I have an Avalonia-built GUI application running, and try to shutdown PC by clicking the power off menu, the app quits before I click the final "Power Off" (screenshot below). If I click "Cancel", sure enough, the app is gone.

None of the apps that I've tested, including the Terminal, FireFox, VLC, and a few Gnome software, does the same behavior. If I click "Cancel", all of the apps stay the same as if nothing happened except Avalonia-built app.

Is this a "bug" or intended behavior? I mean it does not cause any real problems for me, but what if a user changes mind to do a last minute change to the app before closing or if it was a mistake in the first place? I think Avalonia apps should follow other apps behavior if possible here if there is no good reasons to do otherwise. Any thoughts?

Avalonia 11.3.8
Ubuntu 24.04.3 LTS