Great Add-on but is it compatible with FF 15 beta? Rated 5 out of 5 stars

This Add-on is really great and useful.This is not new as I am using it since 2 or may be 3 years.
NOTE:I installed Firefox 15 Beta but the add-on seem not compatible with it and I could not make visible.

This review is for a previous version of the add-on (2.1.7.1).