I'm kinda late but....
Look on the bottom; it says "to service brush, turn unit over". You probably think you already have turned the unit over (it's upside down now, isn't it?). No, turn it right side up and take the cover off the light! (On the whisperTone, that means pressing in on the rightside (as it faces you) and lift up.) You will find the two screws that you need to undo. That solved our "seems to be stuck in the middle" problem. Then turn it back over and, using two flat head screwdrivers, pry at the sides where the tabs are (there were arrows on the rubber molding to show where).
sarah, September 2007