Rated 5 out of 5 stars

I don't understand how to do the Hack to get the add tab button at the right side of the tabs. "To move the New Tab button to the right side of the tab strip, you can use this userChrome hack:
.tabs-stack vbox hbox stack { -moz-box-ordinal-group:10!important; }
Please explain how to do this. Thanks

This review is for a previous version of the add-on (0.3). 

Hopefully this has been solved on MozillaZine!