Enter doesn't do anything in the new login dialog

(Bug, Closed -> Fixed, Priority: Critical, Test Status: No automated tests yet , Reported By Justin du Coeur, )
UX
Summary: When I'm in login, I expect to be able to do username-tab-password-enter, and have that be enough. The new dialog doesn't let me do that.
The relevant code is in UserManager, but I'm not sure offhand how best to make this work.