Just done this twice with different values and same results...
Search for an item, e.g. "auction".
Returns search list.
Use refine options on right, tick "search closed" to see those that have finished.
Returns search list.
Decide to refine keywords further and add "penny" to "auction" already held.
Returns search list of *active auctions* although closed option is still ticked. Have to untick and retick and search again to get the right list.