The retaining clips on the control panel that hold the controls were broken.

I removed six screws to release the panel from the dryer and pulled back the locking tab on the one control that hadn't fallen off and rotated it 90 degrees counter-clockwise. I then placed the controls in the back of the new panel rotating them clockwise until the locking tabs clicked into place. You have to be careful of breaking off the tabs and retainers. (That is why you're replacing the panel after all.)After pushing the knobs on I screwed the panel back onto the dryer. 20 minutes tops.