Soon enough Ms. Foster was popping in and out of her seat like a jack-in-the-box to greet friends and acquaintances , including the owner of the box , who turned out to be Ron Burkle , a supermarket magnate worth $ 2.3 billion , according to the current issue of Forbes , a major investor in Sean Combs 's Sean John clothing line and a co-host of Mr. Combs 's Oscars after-party .