The search function in the latest version of PT3Browser doesn't work, so the mod is next to useless here.
PT3Browser r37287, PeriodicTable-3.0 lib (standalone) r44954.
Access the search box through the PT3Browser FuBar menu "Item Search". Type in an item name verified to exist in PT3 as well as in the PT3Browser menus, such as "Netherweave Bag" (without the quotes). You can verify an item is known via PT3Browser headings such as "Container", "Gear" and so on.
Chatbox feedback: "Not a valid item: Netherweave Bag". Same feedback with anything else known to exist in PT3/PT3Browser.
AFAIK you can search by numerical ItemID only.