[Firefox] Context menu item disapears when restarting the browser

[dedoussis]

How to reproduce:

1. Install the firefox add-on
2. Make sure Context menu is enabled on the Autofill preferences of the extension
3. Visit https://www.spotify.com/signup and right-click on the email input field. You should see the context menu item of the extension prompting you to sign-in to icloud.
4. Shut down the browser process (cmd + Q)
5. Restart firefox, visit https://www.spotify.com/signup and right-click on the email input field. The context menu item no longer appears. Visit the preferences of the extension and confirm that Context menu is still enabled on the preferences of the extension.

[dedoussis]

Other references of the issue:

• https://www.pixelstech.net/article/1542421056-Extension-context-menu-is-missing-in-Firefox-after-restart
• https://bugzilla.mozilla.org/show_bug.cgi?id=1489368