Umbrella Man

Theory that he was a signal to start shooting, or had a gun hidden in the umbrella.    
Louie Steven Witt testified in 1978 at the HSCA explained that it was a symbol of Neville Chamberlin, and protest of Joseph P. Kennedy's policy of appeasement of Hitler.  This is quite a far fetched explanation.  He claimed to have talked to no one. But here he is sitting next to the Dark-Complected Man.

Louie Steven Witt - the same man?

Umbrella presented at HSCA has 7 spokes
Umbrella on 11/22/63 had 8 spokes