Just an FYI - if anyone is running the Fasterfox [http://fasterfox.mozdev.org/] mod for Firefox, your login session will be broken in Roundcube. After checking a mail, or changing to another folder you'll be dropped back to the login screen. The workaround is to disable the pipelining option. So this would also be a fix if anyone out there has monkeyed with the about:config on Firefox and changed the pipelining variable.
P