Using 2 wp_dropdown_categories for search?

Hi!

I have been having some trouble for a while now; i want to have 2 wp_dropdown_categories in my search form, that way people could search in “Category” and “Location” in the same time, OR just choose one or non of it to search globaly.

Butt this doesnt work so great, i have been searching in this forum and on google but nothing that works the way i want.

Maybe 2 categories in the same search doesnt work but surely but in some way i must be able to have 2 dropdown menus in my search? Maybe one category dropdown and one dropdown that lists from a custom taxonomy?

I want it to look something like this: Image

Would really appreciate it.