Subforum-filter for search

The search should have an option in what subforum (on what page) to search, at least in the "Advanced search" on the results-page. That would be very useful, as of now, you can't do many forum-related usfeul things with the search. For example I can't search for help for a certain portable app, if I enter the search term, results of any place on the website (or forums if i selected that in advanced search) are displayed. I bet an often use case is to find something on the website in general, anyhow, to be able to use the search for the forums precisely.
I imagine this is on your TODO-List already, if not it would be great.
Greets