It's a still photo and to me it looks like he's just walking past it. It doesn't help that the picture is so huge and there's no other context.
Long enough to pass Sampras' record
he did sit on the bench reserved for a higher ranked player with a clear name on it 'Djokovic', they switched towels. Djokovic looked confused when he came out, but he didn't say anything ... I still don't believe Fed did it on purpose, but I don't know ... I find it funny in a way. anyway, it's an old story and it's all over the net if you really want to know.