I try to built with Directory plugin a store locator site... I set up custom tax for Dir-location, and need special advanced search to handle these data.
I use plugin WP Advanced Search, simply, well configurable.
after the search submit create a string in URL:
http://mysite.com/?search_query=&, and no results...
when i edit in the URL and replace the string
/?search_query=& with Wordpress standard
/?s= then works wery well.
Where can i fix this? In plugin? Or in a theme search-page template?