Rated 5 out of 5 stars

Thanks Ubhu - your solution works

i.e. Download and intstall the latest nightly build from:
https://code.downthemall.net/nightly/2.0.x/

and Massive Thanks to the developers who continue to support the addon within the existing framework despite the fact it will be deprecated soon. I hope that given your popularity Mozilla may agree to integrate you directly into Firefox (not as an addon) in the future !

This review is for a previous version of the add-on (2.0.18.1-signed.1-let-fixed).