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.
More precisely, it's the Jstree widget that seems broken.
this is scheduled (to be done for paying customer) ~ october
Ticket #4063 - latest update on 2009/09/01, created on 2007/08/10 by Aurelien Campeas