Glad to hear! It was a really stupid mistake (command to reset the query was outside the command that looped through the taxonomies so the taxonomy queries snowballed).
So the logic should be as follows:
1. Get all taxonomies
2. Get all terms within the taxonomy
3. Count the number of posts in the current query matching that term
4. If there are any matches, spit out the term, otherwise continue
Is it just showing the taxonomy label with no terms?
I guess the smarter way to do it, which may save queries in the long run, would be to get an array of all the post_types in the current query, then only get taxonomies that describe those post types.
If you take a look at the Development Version, which is very much, still just a development version, there’s a few more choices in the widget options which may help, and a very rough pass at ajaxing the search results.
As for dropdowns, I think it would be possible, just would have to check the compatibility of wp_dropdown_categories
with wp_list_categories