Tell us what you are trying to do?
I have a search page with a filter for categories. It is showing up fine. But I want to remove some (a lot) of the categories from the select dropdown. Like now ALL the categories for the post shows in the select dropdown no matter what I do.
Example page hidden link
How do I choose what categories that ar showing in the select dropdown?
What you need is a WordPress filter hook for the terms included in the Views taxonomy search filter control so that you can remove the unwanted terms before the select dropdown is generated.
Otherwise, the only option is to modify this on the front end using JavaScript. You should use your browser dev tools to inspect the markup for the select dropdown and add a snippet of jQuery to remove the unwanted options.
Here's an article describing the kind of thing required: hidden link