New Web OPAC - Refine Search Definition

I recently discovered something about the new OPAC that I find a bit misleading. After you perform a search and you are on the search results page, along the left side of the screen it says “Refine Your Search.” Directly below this text is a text box with a Search button. Given the text above it, I have always assumed that using this search box would search for the term in your existing results, refining your search, but I actually tried it today and found that it generates a brand new search.
To further confuse matters, although typing a term in this box starts a new search, it retains the index from the initial search. For example, if you search for the title “Sweetwater” you get 14 hits by a number of different authors. Now say you decide to “refine” your search by entering the name of the author for the particular book you’re after: Siddons. This results in no hits because, even though there is nothing to indicate it, the catalog is still searching under the Title index and there are no titles with Siddons in them. You try again, this time attempting to refine your search by entering a different author: L’Amour. This returns 24 hits (there being that many books with L’Amour in the title), but this is ten more titles than you started with so it's not refining very much. I foresee many confused and frustrated patrons attempting to refine their searches and ending up with confusing results or no results (when they know there should be results).
To me it seems like this search box should either search for a term within the current search results (and this should allow you to choose an index for your search within search) or it should start a brand new search complete with index options (in which case the "Refine Your Search" label should be removed).