This is similar to methodology used in a "Flexbar' mod I use currently. It can be configured so that, for example, right click on a button opens the menu of buttons, then left click (or even move mouse out of button zone) and the menu disappears. Of course all right or left clicks are configurable.
Of course, Flexbar also does things which I know are currently not doable in TBC such as show boxes depending on health / mana status, so I am not sure if this is possible in TBC or not. If it is, it might be portable into Connor's mod.