Firefox doesn't seem to allow selecting from disabled input boxes, so it is not possible to copy the OpenID from the preferences page. This is quite a big issue if you're trying to make a non-techy person an admin as you need to ask them to copy their OpenID and send it to you. I think.

Thanks, Jamie

I've put in a little fix for this.
Comment by joeyh.name Tue Dec 4 18:00:35 2012