According to Osho, openness and witnessing are not two separate states; duality is a trick of the mind. In lived experience they are one movement: if you are open, you are witnessing; if you truly witness, openness happens. Begin from either doorway: open the heart or cultivate witnessing, and in silence the apparent split dissolves into oneness beyond thought.
Opening up and simply watching are the same when you actually do them; only thinking makes them seem different.