This disclosure relates to an interactive display, having a front surface including a viewing area, and providing an input/output interface for a user of an electronic device. A planar light guide (PLG) disposed substantially parallel to the front surface, has a periphery at least coextensive with the viewing area. A light-emitting source (LES), disposed outside the periphery of the PLG, is optically coupled with a PLG input. The PLG outputs reflected light, in a direction substantially orthogonal to the front surface, by reflecting light received from the LES. A light collecting device (LCD) collects scattered light that results from interaction of the reflected light with a user-controlled object. The LCD redirects the collected scattered light toward one or more light sensors. A processor recognizes, from outputs of the light sensors, an instance of a user gesture, and controls the interactive display and/or electronic device, responsive to the user gesture.