"clicking on the "X" at the top right of the last visible application window will exit the application for the vast majority of applications."

It used to be like you describe, but this is a disappearing rule. An increasing amount of companies build apps designed in a way that you need to have sysadmin skills to actually terminate the program for real.

We can't expect Microsoft to require developers to implement this 'X' correctly because Microsoft itself is exploiting this loophole by keeping some of its apps alive when the user clicks the 'x' button.

This is a common trend I already mentioned here several years ago initiated by GAFAM companies to subversively rewrite the signification of common concepts that they disagree with: - "no/decline" -> maybe later - "no/decline" -> skip for now - "no/decline" -> remind me later - "close" -> sleep" / run into background - "delete data" -> hide/hide temporarily - "delete account" -> deactivate (but keep everything) - "somebody" -> best friend - "buy/pay" -> rent - "configure" -> submit your preferences, we will take that into account etc.

All these concepts are being actively stolen from the population and I am terribly saddened to see the vast majority of our regulators have absolutely no clue about the long-term consequences of this concepts being stolen/rewritten without tacit consent.

So, yes, Discord rewrote the 'x' button but to be honest: who cares? Apparently only too few.