Stop in for a cup of coffee

With the window casing where it is Mike, I'd say remove the panel up to the height of the refrigerator and cap it with a piece of trim or something. The shelf would stabilize the top portion. Matching a cabinet might be a PITA

That'll avoid the footprint on the ceiling I'm guessing is there.

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I put a vote in to remove wall altogether. Let it "breathe". Also, makes it easier to pull out and clean once or twice a year.