I wanted to comment that for a long time I had this error when I enable the extension

What I have is an error reported by the IdexedDB error handler:
`e.target.error.name`: 'UnknownError'
`e.target.error.message`: 'The operation failed for reasons unrelated to the database itself and not covered by any other error code'

https://bugzilla.mozilla.org/show_bug.cgi?id=944918

The solution for this was to go to `about:support` to find my Profile Folder and to delete the contents of the `storage` folder from my profile.

Now I came back to my preferred extension!