Thanks for the reply Dansyacht.
If only it were that simple. The format menu bar sits towards the lefthand end of the dock with the top of it poking just above the shelf but below the top of the icons so it is not possible to grab it. However, if you move the dock elsewhere to reveal the bar and then try to drag it to where it would be visible above the dock it is immoveable. However, Mission Control will allow it to be moved from desktop to desktop where it just springs back to it's original position (but on a different desktop).
The bar is part of the TextEdit Save box. Try to save a TextEdit file and when the Save box comes up it is the icon towards the bottom of the box which says <"File format: " + the adjacent menu bar>.
It is as though a mutant clone of the Save box icon has escaped in order to rise above its station to try to become a Dock icon. Sweet but very annoying.