Ok, hacking in /usr/lib64 does not work :< Probably better that way:)
EDIT: open remains the question why it repeats on repeated characters being entered into the same field. That function should only fire on FOCUS if I understand the FormAssistant.
Maybe that’s the gist of the performance issue. If the form is being repeatedly checked with dom methods to determine if it’s a password user field? Hmmmm. Ouch.