Unified search for file names and content

On the Items search page, the search field defaults to searching in document names:


Everyone here assumed that the button next to the search field with the two arrows is the "Go" button, and we were surprised to find it switching the search mode to content:


Is there a reason to differentiate? Why shouldn't document names *and* full-text contents be included in search results? After all, I don't do a web search for titles and content separately either.

If the two need to stay separate, can we maybe get two input fields, to make it clearer?