The Jiggs is up

Sent by Dirk the Daring, who says “This may be from 1948, but I still don’t get it.” And some of us who are from 1949 still don’t get it either.

And to start off, who are the characters in the final panel? The guy stretched out must be the tall loudmouth from the main encounter. But the guy across the street is not wearing Jiggs’s patterned waistcoat, and might be just a passerby / witness. But this still leaves open the question, What exactly was the bone of contention?