It's a messy process, but here are steps that work: - click settings>general and scroll down to config editor - search for toolkit.legacyUserProfileCustomizations.stylesheets and change to true - then you need a folder named 'chrome' in profile, and a userChrome.css text file in the folder (with content shown below). - exit and restart TB and it should work, although I've sometimes found I have to restart TB twice to see changes in userChrome.css - Below is content for userChrome.css

/*  #######    */
@namespace html url("http://www.w3.org/1999/xhtml");

#toolbar-menubar {
  order: 1;             
}

unified-toolbar {
  order: 2;             
}

#tabs-toolbar {
  order: 3;              
}

David, I owe you a beer. Worked on the first restart...and of course it wasn't easy.

You're very welcome.