I am including your plugin in a website I am working on and this website is for a travel guide company that does business in two cities with multiple pages/cat's/tag's/etc...
Ok, so this is how this site is setup, each city has multiple pages (Dining, Attractions, etc...) and on each of those pages are listings and your search module. I want each page to be able to only search criteria specific to it. IE; Dining => Tags (American, Asian, BBQ, etc...) & Categories (Downtown, Southside, Northside, etc...).
I have yet to figure it out but using your search module, I am unable to tell it not to show certain tags in its drop down panel. Lets say I only want to display Dining ares, well the drop down won't exclude tags that refer to Attractions, etc...
I know I'm probably not explaining myself that well and I am sorry for that. Any help is appreciated!
http://wordpress.org/extend/plugins/wp-custom-fields-search/