Rated 5 out of 5 stars

Excellent addon, but doesn't it overlap with Firefox v.42's new functionality?

LATER: @ Daniel: thanks for your detailed reply, much appreciated. So I can feel comfortable letting your addon run concurrently with FX42, which is what I wanted to know.

This review is for a previous version of the add-on (2.9.4). 

Only somewhat. For instance, 42 still doesn't allow you to save, edit, or delete your passwords straight from the page context menu (with SPE, right-click on a username or password field in a web form, and you get those options).

You have to make your passwords visible in order to edit them (with SPE, they can remain hidden from anyone looking over your shoulder).

Most importantly, you still can't input logins on your own, which means that if the Password Manager is unable to recognize a web form for whatever reason (say, it's built after page load by scripts), you're out of luck.

To be fair, the things that used to confound the Password Manager still confound SPE. I should look into what Mozilla has done to see if SPE can be improved too.