How to finalize a smart filter?

Question

1C-Bitrix

I have the output of elements through api, I also customized the filter template.
When there are no options, the items in the filter are darkened, but not always.
For example, I use my "in stock" checkbox property and display items based on availability.
But the filter, of course, knows nothing about such a tick. It turns out that it does not obscure the item.
How to do prefiltering or, in other words, make a smart filter take into account my property?

Answer 1

The property has an option "Use in smart filter" - tick it!