Help improve search behavior

[David N.]

With the new search filter inside the search box in 4.7 I've noticed that many times I am browsing a topic, then do a search and find nothing, only to later realize that the search box was automatically set to search only that topic. 

I wish that at least there was a link or a button in the search result that said something like "You were searching only that topic. Do you want to extend your search to the entire forum?"