Spectral View 'circle' cursor - why won't it show?

I have been using the spectral view to great advantage lately....erasing out clicks in the middle of words, etc.  Usually, when you move your cursor to the spectral view area, it turns into the circle that is your 'eraser'.  Suddenly, this afternoon - it no longer appears when my cursor is in that area....  Anyone have an ideas of what changed or how I can get it back?

Much appreciated!!