Secure Login is not (and will not be) fully e10s compatible. Please try Secure Login (WebExtension) replacement if you are on Firefox version 51 or above.
Secure Login's main feature is similar to Opera's (the browser) Wand login.
* Works out of the box without any configuration needed.
* Login with one click or a keyboard shortcut (automatically submitting the login forms).
* Easy and convenient selection for multiple logins (multiple users)
* Provides direct login to any site from the bookmarks (using the "Secure Login Bookmarks").
* Integrates with Mozilla Firefox password manager.
* Provides easy access to the saved passwords.
* Helps to protect you from phishing.
* Shows the login URL(s) and the number of available logins in a tooltip of the toolbar button and the statusbar icon.
* Can be set to automatically search for login data and highlight form fields.
* Can be used with a toolbar button, a statusbar icon, a keyboard shortcut or via the context menu.
* Completely customizable interface (buttons, icons and menus can be enabled/disabled).
* Provides a customizable keyboard shortcut
* By default only active on login so it doesn't consume any system resources while surfing.
* Can fill out additional form fields using the Autofill Forms add-on.
* Possibility to play a sound when logins are found or when logging in.