#6 - Jan. 28, 2007, 10:04 p.m.
Some UI mods add sub categories by simply restricting search results, but by default no actual filter exists for sub categories in trade goods at the moment. We are still intending to make changes to the auction house interface at some point in the future; however categories are literal translations from the in-game item hierarchy. To add or remove search subsections, and move around items, is a large undertaking. It's a UI we definitely see room for improvement in, but there aren't any currently announced changes planned.