I would like to have an undo such as ctrl-z. I would like to see more versatility in the call-outs. Nit-pick: please correct your spelling of the eraser icon, you have it incorrectly as "erasor"

I would like to have an undo such as ctrl-z. I would like to see more versatility in the call-outs, your basic box just isn't enough. Nit-pick: please correct your spelling of the eraser icon, you have it incorrectly as "erasor"