I had that problem for a while. It's not that it's not showing up, it's just not being placed right. It's BEHIND your main toolbar... Not that that helps. For a while, I thought that it was an add-on doing it, but it even happened to me when I turned off all my add-ons.
My solution ended up being downloading Bongos2, and making my own user interface. It fixed my problems, made key binding a LOT easier, and now I have a nice-looking, easy interface.