'Narrow your search" always gives a long list with all options, irrespective of whether there are really items in search results that apply to that option. For example if someone searches for "Karl Marx" there are certainly no shoes, jewelry or watches in the search results, leading to an empty result list. So these empty categories should be left out.

If possible it would be awesome, if the number of items were displayed along with the category. So, from the drop-down list we would know that there are 679 books and 23 Videos applying to the search.