DIAGNOSIS The Top Track silverware rack has two small plastic hooks that latch onto the rails of the middle rack. If it's falling, those hooks aren't fully engaged, or the middle rack isn't pushed all the way back.
FIX First, remove the top rack completely. Look at the two rear hook assemblies. Make sure they're not broken or bent. Now, push the middle rack ALL the way back into the tub until it gently bumps the rear wall. You should hear or feel it settle into its full rear position. Now, align the hooks on the top rack with the metal rails of the middle rack. Lower it straight down. You should feel a positive 'click' or engagement as the hooks slip over the rails. Give it a gentle tug forward to test it's secure.
IF THAT DIDN'T WORK If the hooks seem loose or damaged, you can order replacement hook clips from KitchenAid. They typically snap into place on the rack frame. The part number is often on the underside of the rack itself or in .
HEADS UP Don't overload the top rack, especially with heavy items like large spoons or ladles. The weight can cause it to sag forward and disengage from the hooks, even if they were initially latched correctly.