[debugnik]

None of those are supposed to stay on the background (specially not browsers, which are sandboxes for untrusted apps nowadays).

But if I click X on my email client, it keeps receiving email; if I click X on my torrent app or JDownloader, they keep downloading; if I click X on Steam, it keeps updating my games; and if I click X on a chat application, it keeps receiving messages and, yes, usually keeps voice chat open.

And BTW, browser tabs sadly do stay open in a twisted way: notifications, often malicious for the kind of users that accept the prompts without reading.

[LelouBil]

In this case, Discord is still transmitting data after you press "X".

It is the wanted behaviour, of course, but I don't find it weird that having a message explaining it the first time you close the window should be mandatory.