1. A method of modifying an annotation input on an interactive display in an interactive input system comprising: determining a region of interest about the annotation; determining reference pixel values in the region of interest of a reference frame; storing the reference pixel values in memory; determining current pixel values in the region of interest of a current frame; determining whether the current pixel values differ from the reference pixel values; and fading the annotation when it is determined that the current pixel values differ from the reference pixel values.