Right, @stella111? They look like just a slab of metal until you see the latch rollers, the interlock, the whole setup. It's a whole little machine hiding in the wall. Dylan's comment makes it sound so basic, but there's nothing simple about that puzzle.

Guess my IKEA shelf is an antique.

Standing there staring at a piece of metal for five minutes seems a bit much. It's just a twist in some steel, not a cure for a disease. That old smith advice sounds like something you'd get on a fortune cookie. Glad it worked out, but maybe take a walk next time.

Did you check the O-ring before you put it in? I've seen cheap ones crack and cause a leak that blows the whole thing.