A method for gesture recognition in an optical system using a touchless slider is shown. This invention particularly relates to novel azolidinedione derivatives of the general formula, and their pharmaceutically acceptable salts, pharmaceutically acceptable solvates and pharmaceutical compositions containing them. A layer of passivation is deposited over the layer of dielectric and a thick second layer of dielectric is created over the surface of the layer of passivation. The availability of the callee can subsequently be displayed to the caller, or any other individuals who have been granted permission by the callee to be notified of the callee’s availability.