When Simon Oakland is preparing to jump out of the window in the courtroom, you can see his shadow on the backdrop of the skyscrapers behind him.
When Cowboy jumps from the fifth floor window, the painted cityscape behind him flaps as he passes narrowly by.
When Max finds the Cowboy for the 2nd time in his bed, he leaves him to get up, and the blanket is nowhere near the Cowboy's chin. When the scene shows the Cowboy in bed again a few seconds later, the blanket is in a different place near his chin.