Since about two weeks, pressing Alt-F4 on the desktop no long offers 'Shut down' as the default action. Instead, it shows 'Switch user' on top:
So I can no longer just press Alt-F4 and press return, which is annoying.
Strangely, it also always shows 'Update and restart' in the option dropdown, even when no updates are scheduled:
Now that I think about it, I wonder why it doesn't offer 'Hiberate' as an option, because I do have that enabled. So clearly, that dialog somehow got messed up.
I already found this article that shows a registry hack to revert the default action back to 'Shut Down', but it has no effect. I also tried choosing that 'Update and restart' option to see whether it would disappear, but it does not -- and in any case, 'Switch user' is still on top and default.
What might be causing this and how can I fix it?