I think the best fix for this is as stated in comment 6,
"If the password was filled in -> onUserNameFormFieldChange if
strToLower(username) === strToLower(stored username) && username !== stored
username then prompt "Update|Save As New|Not Now|Never for this site" - if
change, update username.
Either way, if a change is made to the username field by the user Firefox
should never overwrite this change."
This seems to deal with both this problem, and the original problem for bug 447788.
I think the best fix for this is as stated in comment 6, ieldChange if username) === strToLower(stored username) && username !== stored
"If the password was filled in -> onUserNameFormF
strToLower(
username then prompt "Update|Save As New|Not Now|Never for this site" - if
change, update username.
Either way, if a change is made to the username field by the user Firefox
should never overwrite this change."
This seems to deal with both this problem, and the original problem for bug 447788.