Goodbye Girl, The (1977) Easter Egg - Not Nina Hirschfield!

In classic balcony arguement scene where Richard Dryfus runs down the list of personal problems to Marsha Mason (pretty run of the mill and over acted) a gentleman walks out of the ground floor onto the sidewalk dressed in typical black with a black beret and a big black artist's portfolio.
It's white bearded Al Hirschfield. He was the twentieth century's most famous caricturist of Broadway plays and musicals. TGG was a screen play about actors and the stage life in NYC.