Has anyone else had any problems with the keyboard backlight? it seems like it is quite inconsistent. I'll open the keyboard and the backlight will turn on. then it will go off halfway through typing a message. Then on. Then off again. Don't know why. Right now, it won't go on at all (3:15pm in a bright office). So I am assuming that there a light sensor that I am covering up or not seeing... and it won't go on right now because it is bright in here? Thoughts?