Rated 3 out of 5 stars

yazan: windwardman tarih: Tem. 9, 2015 ·

Using Firefox 39, this add-on is keeping me from switching back to my inbox in Yahoo mail from a full-screen e-mail. Put another way, if I double-click an e-mail to read it full-screen, clicking on "Inbox" from that e-mail does nothing. Clicking "Compose" has no effect either. I have to exit and log back in.

This review is for a previous version of the add-on (2.5.1.1-signed). 

yazan: Diego Casorran (Geliştirici) tarih: Tem. 12, 2015 ·

From a technical perspective, i think it's their web-mail what is doing something wrong, one thing you could try is to check it with the w3c validator (https://validator.w3.org/) - I.e: paste the Page Source there to see if it throws any error, that should bring some light on the matter.