Rated 4 out of 5 stars

Nice addon.
Fixed bug with deleting overlays in my local installation, but how soon will be an official update?

This review is for a previous version of the add-on (1.5.6). 

The next release (1.6.0) which fixes the delete bug and adds a couple of new features is currently in the review process and should be out shortly. Usually it takes 2-3 weeks to get approval from Mozilla Add-ons team.