Need to Fix an "Open" Button on the Microwave? I Think You Nailed It
"Dry here to open?" So it's some kind of moisture-activated locking mechanism, where dehydration makes said mechanism weigh less and rise, thereby releasing the lock and opening the door?
Unless... oh wait, I see what it says now. Never mind, carry on.
~Not-"Not-So-Handy-Andy" Jack