> The customer must be able to deselect it if he wants,
but how would you know he did that if it’s not shown ? (other than knowing and remembering for each product what was there in the first place)

anyway, it works differently (for precisely that reason), so here are a couple of suggestions

you could enable
“WPPizza->Ingredients->options : Show de-selected pre-selected ingredients ?”
which will say “no pineapple” if it’s deselected

alternatively , you could add an ingredient called “No Pineapple” (without it being preselected) and allow the customer to select this.

generally speaking anything that’s selected will be shown (preselected or otherwise)

As a sidenote: Do you really need to allow someone to deselect pineapple from a Hawaii pizza?
that really just makes it a normal pizza, no ?
Surely noone will even consider ordering a Hawaii pizza if he/she doesn’t want pineapple in the first place – but that’s just my thoughts there ….