I saw a suggestion while reading on this topic elsewhere to use rubber foam pipe insulation (like you would use on the condenser pipe between your air conditioner compressor coolant line). It is black and smooth-rubbery and could be cut to fit and tucked into the gap. Sounds like a cheap solution.
My Bosch brand dishwasher came with flat black rubber trim pieces attached to the sides already. They folded in as necessary from their naturally-extended position to close any gaps on the sides.
These guys sell some kits, and your manufacturer may have one, too.
»www.repairclinic.com/Dishwasher- ··· im-Parts--
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