Blooper

Various episodes disagree about the length of time the Hartleys were married before the series narrative starts.

Howard Borden is employed as a navigator for an airline, but by the time of the show's setting the navigator job on US airlines had been eliminated. If however Howard had been employed by a foreign airline, he most likely would not have been based in Chicago. Based on destinations he mentioned during the course of the show (domestic), this appears unlikely.

There is a window behind the headboard of the Hartley's bed which shows a view of the city. However, if the orientation of the building's hallway is correct- apparently leading off to the left from the Hartley apartment front door, then the window should open onto it.