Thanks for the response and help. I am using it on a laptop with a trackpad, so no scroll wheel. Is there another way to resize the brush? looking forward to where you will take this.
Typically, most laptop track-pads will interpret a dragging motion along the right-hand edge of the track-pad as a scroll-wheel. Check the track-pad driver settings. The track-pad itself may even have a scroll-bar marking on it, showing that the function is active by default.
