When you mouse-over the Show/Hide editor tools tab, there needs to be some affordance that it is clickable.

We certainly need to change the mouse pointer,

I suggest that we also make the text red and underlined, like hovered links. In fact, adding href="#" might be a way to achieve that. (It needs to look a hovered link in the current theme, whatever that is. I think the unhovered state should probably stay as black text.)