Rated 5 out of 5 stars

Thanks for providing the option to move buttons right before the tabs. But is there a way to show the actual hamburger menu symbol with the three horizontal lines instead of the big blue Thunderbird button?

EDIT: Amazing, thanks for the quick update! Really appreciated!

This review is for a previous version of the add-on (1.3). 

I've uploaded now version 1.4 which has an option to disable the blue button.