Doesn't work as well as I hoped Rated 2 out of 5 stars
Looks like I don't get what this addon actually does.
The two websites which don't allow me to login without entering username/password still don't work. I can save a password, but it's no use because the fields stay empty.
The pages are:
Not a perfect solution
Unfortunately, SPE only helps if Mozilla's password manager can understand the login form in the first place. Both of those pages break its expectations (one regular text field followed immediately by one password field), so one must resort to stronger measures, such as bypassing the password manager entirely.
One add-on that will almost certainly work with both of these is iMacros for Firefox: https://addons.mozilla.org/addon/imacros-for-firefox/
Be sure to set a master password (it has its own in its add-on options) so you can have your passwords encrypted.