Dear Maintainer,

I started my computer and was presented with the GDM login screen. I
clicked "Not listed?" and was prompted for a username. I then clicked
"Cancel" but I was not returned to the main menu; nothing visible happened
at all.  I therefore typed my username into the box and clicked Next. I was
prompted for my password, and the "Cancel" button on that page worked,
and returned me to the main menu.

The bug can also be produced if Gnome is locked from the power menu and
you try to log in as a different user.

Thank you for an otherwise nice piece of software!

George Bateman.