I'm looking for the light sensor but am not sure of location. I've read several posts about the lighting sensitivity on the D4 keyboard and get there is a sensor and all is aimed to save battery. One post described location along the side adjacent to the button on top that activates the screen. Is the tiny hole the light sensor? When I type, that area is always covered but the light still doesn't come on when covered, even in pitch black. However I've noticed when I cover the front camera eye, the light comes on exactly and remains on as long as I keep that covered with my index finger. Is it possible there are two sensors or is that the actual sensor. I get nothing when the edge is covered, which is always while typing.