Hi MO, first of all, thanks a lot for your rating. I'm sorry that the extension is not working as expected for you.
To troubleshoot this issue, we'd need more information about your system (i.e. what OS and what Firefox version do you use?). It would be glad if you could open an issue on https://github.com/rugk/mastodon-simplified-federation/issues and fill out the details there, so we can fix this problem in the next release.
One side note though: Where is it greyed out? The extension has no visible extension icon, so there should be no icon to be greyed out.
I hope this explanation helps. Also note that you may, at any time, adjust your rating.
