I don't know if this has been mentioned before or not, but Fox has messed up the season 4 opening credits on several episodes. There are a few episodes where the opening credits are shortened and don't even include the orange background stuff. Two episodes have the completely wrong opening credits. One episode uses the 1st and 2nd season opener and one epidoe uses the season 6 (I believe) opener that shows the Hartley's new apartment after they move to the 10th floor. This isn't the first time that Fox has messed up the opening credits on this show, but the mistakes on season 4 really stuck out.