During the trial, when Adam Bonner is talking to the jury, he makes a few slips of the tongue. You can see Amanda's hand jump to cover her mouth to keep from laughing in several shots, while in other shots her hand is on the table in front of her.
Midway through the trial, Kip uses the Bonner's piano to play an early version of a new song he's writing that is in such rough shape, it doesn't have complete lyrics. Yet shortly afterward - and long before the trial is over - the song has already been recorded, played on the radio and is reportedly a big hit.
Even though Adam and Amanda are reading about Doris Attinger's arrest in different morning newspapers (he the "New York Globe", she the "New York Chronicle"), the back pages of both papers are identical.
When Adam slams the door as he exits their apartment after an argument, he slams the door and the wall shakes. As Amanda slams the door after him in anger, the door frame can be seen to be coming apart, revealing that it is a set, not a real apartment.