You can click on the Google or Yahoo buttons to sign-in with these identity providers,
or you just type your identity uri and click on the little login button.
we believe this is fixed
unique together constraints where seriously fixed in 3.18.0, let's see if this is still a problem
Ticket #1625101 - latest update on 2014/09/24, created on 2011/04/18 by Florent Cayré