Good job! Rated 5 out of 5 stars

Thank you for this great addon!I have a feature request that may not be a fix to Firefox's UI, but I need it. That is tab sliding instead of drag-n-drop. It is in IE9, Google Chrome 10, Opera 11, Apple Safari 5 etc. Why it is not in Firefox?
EDIT: Ok, I wait ;)

This review is for a previous version of the add-on (1.4.0.1-signed.1-signed). 

It would be hard for extension to do that, but it should be fixed in Firefox 5 (expected to release in 3-4 months).
https://bugzilla.mozilla.org/show_bug.cgi?id=455694