I want search to return all items when no keyword is entered (the default behaviour is to return no items).

I'd like to be able select a category from the drop-down on the advanced search page, not enter a search term, click search and see all the items in that category.

You can do this manually by entering '%' into the keyword field (it's the mysql wildcard). However if I try to override $_GET['keyword'] to be '%' when it is empty, zen cart redirects to advanced_search instead of advanced_search_result.

Any suggestions?