Tag up on fly ball

Question
Kevin...a ball is hit to the outfielder...it hits his glove and pops up in the air.  Runner on 2nd base takes off for 3rd...2nd outfielder catches the ball (it has not touched the ground).  Does the runner have to go back and tag up?   I have heard that the runner does not have to wait for the catch...that once the outfielder touches the ball, the runner can tag and go.   This would be a rare but real situation.

Answer
Despite my natural instinct to say that the runner has to wait for the catch to be complete, it is true that once the ball is touched by the first fielder the runners are able to leave the base. This is one of the few rules that I do not agree with but never-the-less has to be followed.