Not sure if this is by design ..
I've added a keyword to a couple of my entries as a test

.. When I go to the search page and enter my keyword, untick the search option "title/description", only have "Keywords" ticked and press search I get the list that I am expecting of links that have the keyword. But it also highlights in red the word in all the links in which that word appears.
I would of expected this if I had "title/description" ticked as that's what it's searching for. I wouldn't expect to see this if it's unticked.