Should you correct a person with dementia when they mistake sugar for salt and so on?

I would in a nice way. I might say,: Oh, let me get that for you. It's in the wrong container. I mix it up all the time." And treat it lightly and move on. Then, try to separate the things so they are more difficult to mix up down the road. I read places that people with dementia don't like to be corrected, but, they might if they were going to ruin their nice cup of coffee with a teaspoon of salt.

If Dad starts to put antibiotic cream on the toothbrush, I intercept and hand him the toothpaste with some comment on how much they look alike. If he puts sour cream on his roll instead of butter and seems happy eating it, I just smile and ignore it. Everything doesn't need to be "right" it just needs to be safe and keep us moving on down the road.

Well I wouldn't let them put salt in their coffee or sugar on their french fries - would you? There's a difference between saying with a smile "oh dear, I think that you grabbed the salt by mistake, let me get you the sugar !" and growling "oh for &%@# sake, what do you think you're doing, can't you see the difference!"... right?