Rated 5 out of 5 stars

Does what it says it does.

Would be nice to only have this affect empty tabs (about:blank), as Firefox already has insertRelatedAfterCurrent for tabs opened directly from a page, and this seems to alter some behavior with that (but I don't think the tab's 'open' event has access to the URL, as it fires as soon as a tab is opened, so they all use "about:blank"...)

This review is for a previous version of the add-on (1.0.1-signed).