Kevin, although I empathize, we generally mirror user interface
changes in the browser that Mozilla makes or add-ons start having
problems. For Firefox 23, Mozilla removed the ability to auto-hide
the tab bar (see https://bugzilla.mozilla.org/show_bug.cgi?id=855370
), and obviously you aren't the only one who dislikes this change.
However, this change is a prerequisite for Australis and its
dependencies, and we can't make it to Firefox 31 without Australis;
additionally, reverting this change requires moderate surgery on
TenFourFox that can't be carried forward anyway. It's not practical
to do. Sorry.
I don't know what to tell you about SeaMonkeyPPC; I don't
maintain that project.