When Mike and bunch chase Alices swindler out the back. Mike grabs sliding door handle through the imaginary glass and pulls the sliding door open. There is no glass so as to not reflect the studio lights and crew. Also Gregs green striped shirt appears on Peter and even Jan in subsequent shows over the years as they outgrew it. The show where Marcia is babysitting Mike installs a chain lock on the front door. In subsequent episodes it disappears and reappears as old prior footage of the door is shown.