Just before Spudsy enters, his wife puts her coffee pot down -- inside Perry's straw boater on the table. Spudsy knocks and enters. Cut back to his wife with the coffee pot in hand (ready to throw), and Perry's hat is back on his head.
Della has a steno pad in her right hand as she sits down on Perry's desk. The camera switches angles and the steno pad is in her left hand.
When Mason enters Patton's apartment, he locks the entry door from the inside so his search won't be disturbed. After finding the body, Mason exits the apartment into the hall, and the entry door is once again unlocked.
When Johnson takes the phone to talk to Mason, he puts his right hand inside his coat, but in the next action cut it is outside the coat by his side.
When Mason goes to Patton's hotel room, he enters the darkened bedroom. The light coming in through the window goes off before Mason switches on the room's lights.
As Dr. Crocker is performing a fluoroscopic examination of Perry, a static x-ray image projected on the viewing screen. If this was a true fluoroscopic exam, movement on the screen (ie breathing) would be visible , as fluoroscopy provides live moving images.