Brad,

I assume you have the Firefly control system, if so, holding the button will invoke the dimmer mode. First press and hold dims the lights, next press and hold will bring them up to full.

Another "feature" that may not have been explained is if you press all lights off when you shut lights down pressing the all lights on will only turn on the lights that were previously on. If you hold the all lights on button, ALL lights will come on at full brightness.