Alt-F4 exits the application

[LoopinFool]

The close box minimizes the app to the taskbar as one would expect for an always-on app like Join.
But I'm a keyboard-jockey and found that Alt-F4 exits. I may be able to work around this with AutoHotKey but I don't feel it's the correct behavior. Alt-F4 is supposed to be Close, not Exit.