Developer reply by Realraven (Axel Grude)
Rated 2 out of 5 stars
Firefox 50
Not compatible with multiprocess ("Add-on Compatibility Reporter" says it): http://storage8.static.itmages.com/i/16/1125/h_1480104853_5482066_2c13034c4c.jpeg
https://addons.mozilla.org/es/firefox/compatibility/reporter/QuickPasswords@axelg.com?appver=
Here is a bug report and a version that hopefully fixes it:
https://www.mozdev.org/bugs/show_bug.cgi?id=26329
To create your own collections, you must have a Mozilla Add-ons account.