Don't work with Author Australis Theme 2.0 Rated 4 out of 5 stars

Good! Must be integrated in Firefox by default.

But, don't work with Author Australis Theme 2.0

This review is for a previous version of the add-on (1.0.1). 

Hello,

Please try version 1.2 https://addons.mozilla.org/en-US/firefox/addon/tabs-always-in-titlebar/versions/1.2 Australis compatibility should be fixed.