It creates some sort of invisible popup window which sometimes prevents the Fireforx tabs from being closed. It does not happen always and I had hard time figuring this out.
If you click the close button of a tab a toolwindow close button appears over the Firefox main window close button and the tab close action is prevented - it is how I found this out.
I like it overall, but that is unacceptable.

does its job, highlights do follow and no follow links

I love this extension. I've been using it for years. Thanks Igor :)

I've been using this extension for long, for checking nofollow backlinks

Excellent add on

Hey, I would like to rate you 5, but I have a suggestion for you like my old No Follow extension; please add something to highlight all links in the text while highlighting nofollow as red.

很好用~~

Addon works perfectly fine, nofollow links are outlined in red.

Works very well. Thank you!

I used on other one but was obsolete with FireFox 56.
It do what he promise

Thank you very much for your addon! But it doesn't save options. Each time after restart of the browser I have to configure it again and again. Please fix it! Firefox - last version.