Comment # 2 on bug 1000514 from Wolfgang Bauer

Interesting.

I wasn't able to reproduce at first (same as bug#1000510), but indeed that
happens on first login on a fresh user account.

It seems a bit more random though:
The first time it happened immediately when I clicked on the chooser, the
second time it happened when I clicked on "Cancel".

The desktop doesn't really crash though, it apparently just gets "hidden" by a
black background.
Clicking on the panel makes it reappear, here at least.