Just what I have been looking for (updated review) Rated 5 out of 5 stars

This add-on is great. Exactly what I've been looking for, for a very long time. Great idea to not only modify middle-click but to add a modifier key (shift) to give us one more option. Nice job.

I had originally thought this addon caused tab groups button not to work. The developer quickly contacted me (reply below) and we found out it was a conflict with the LastTab extension. I don't use that extension anymore (for easier to navigate with Enhanced Middle Click) so I uninstalled LastTab. Everything works perfectly now.

This review is for a previous version of the add-on (0.3.1). 

Thanks for the review

The thing is that the "tab groups" button works in my firefox v15.0.1. Could you tell me what firefox version, OS and addons are you using? So I could try to reproduce the problem and fix it. You can also contact me via email in my profile.

Regards