A display includes a light-transmissive planar member with side edges and opposing surfaces. A plurality of light sensors are disposed along at least two of the side edges of this planar member. These light sensors are disposed to detect light moving through the light-transmissive planar member by internally reflecting off the aforementioned opposing surfaces. A control circuit detects a position of a light-emitting stylus with respect to the display by using the plurality of light sensors to detect light from the light-emitting stylus that moves through the light-transmissive planar member via the aforementioned internal reflections. By one approach the side edges the light-transmissive planar member are inclined at other than a perpendicular angle with respect to the aforementioned opposing surfaces.