Firefox doesn't recognize RT 3.8.7's username/password fields

One more nit I found with my upcoming upgrade to 3.8.7 involves Firefox.
Firefox no longer offers to save usernames and passwords. Does anyone
know why this might have happened and what I should do to get Firefox to
recognize the fields?

David Griffith

A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?