Assuming that Mozilla works like IE, I think this is because the page has two password fields, and no plain-text one for Mozilla to store. I've asked before for this to be changed, but Michel thinks that having the username visible reduces security, even though my bank doesn't share his opinion, and he doesn't do a secure login anyway, as far as I know...

What, you don't think there's someone looking through your window with a telescope just waiting to get a glimpse of your username to help them hack into your UT account and post naughty messages?

Michelle