First thing I noticed - Nice little light source right there in the tent ready for you to fuck it up when you forget to click it off because you didn't see it because the light was on...
Are you talking about the display? If so, then I'd be willing to bet it times out and turns off after a specified amount of time of button inactivity...or it could just turn off completely when the light turns off. I know I can set the display for my AC infinity fans to dim down when I'm not adjusting things so I'd be shocked if they didn't do the same with the light controller.
Edit: I also just noticed this in the description "Controllers can be detached to be mounted remotely and are built with extension ports to provide programming to additional LED grow lights. "