I've had mine for years, and very good it is too, I have sometimes idly wondered why there are two buttons on the top, I know the black one stops the spinner, but the other one? I admit, it hasn't kept me awake at night , I assumed it was one of life's mysteries, the Sphinx, lost teaspoons, people who find Mrs Browns boys funny, astrophysics, the OXO good grips extra button...........
I just found out! If you hold down the plunger bit and slide the white button over it keeps the plunger pressed down so the spinner takes up less storage room.
Well, there's a thing, I am feeling quite proud of myself for accidentally working this out.