And no - I too did not know I had this imperfection. Now I will lying awake at night... ;)
... Because, the plugin would not work for me. ;(
Attempting to Install, Firefox reports:
"ClassicFox 2.1.1 could not be installed because it is not compatible with Firefox 3.6.15."
I see this tempting item has not been update in going on 3 years. I have considered learning to do FF extensions: if this is a modest code - and it sounds like it may be - perhaps it is a good one to cut my teeth on.
I love this extension and I'm extremely grateful to Kai Liu for creating it.
As others have said, it fixes a somewhat subtle issue, but it does so in a flawless manner and works perfectly.
It may seem trivial to those who don't actually use 3D looking user interfaces, but for those of us on classic looking XP or Windows 2000, it not only significantly improves the look and consistency of menus Firefox / Thunderbird, but it also makes usage more intuitive. It becomes immediately clear that the drop lists on back and forward buttons work separately to the button itself and that these drop lists are clickable. It even has a nice 'sinking in' effect when you press it.
The fact that the author has made this extension Firefox v3 compatible is yet another bonus.
When Windows XP is in "Classic" mode, the menus in Firefox's default theme don't show up three-dimensional like they should. ClassicFox fixes the appearance of the menus for a more consistent operating system appearance. Only the most observant among us have noticed the subtle inconsistency, but this add-on serves that small group of folks very well.