Comment 33 for bug 382626

I personally think that the button should toggle between an some kind of icon representing a mouse/cursor (to switch to breadcrumb mode where you click on buttons) and one representing a keyboard (to switch to text entry mode).

It makes sense to me because most users click the buttons in icon mode and type in text mode, and would be able to make this connection pretty easily. I attached a quick mockup of what I mean.