Lower rack plastic roller system - is a poor design for retention.  Left side (facing) separates from rack when rolling a full rack onto the door.  Problem is the molded twin plastic blocking tabs (on the roller system) do not provide adequate retention to prevent the roller mechanism from separating.  The roller assembly uncouples and then slides rearward, separating from the rack.  Both retention tabs are there but have inadequate deflection to hold the roller system in place.