Continuity mistake: In the escape scene when Hal runs out the store his boss presses a button to lower the shutters. This causes the pencils to fall out of the cup but in the next shot the pencils are back in the cup and roll off the table into the fan.
Continuity mistake: When Lois and Hal work to draw up their will and then argue about Francis, Lois' hair changes repeatedly when the camera angles continually change.
Continuity mistake: This mistake happens in the scene where Dewey bumps his head. In one shot, Lois puts her hand on Dewey's shoulder, and in the next shot, her hand is on his chest.
Revealing mistake: In an imagination sequence Reese and Malcolm are throwing around Jamie, but you can see it is a doll.
Character mistake: When Otto tells Francis he has to put a horse down, Francis objects saying he's never killed anything bigger than a poodle, and that was an accident. However, in season 4 (episode 11), Francis accidentally killed Otto's pet cow. (00:11:30)
Continuity mistake: After Stevie becomes catatonic, a wrapper from a chocolate bar lands on his face, covering his glasses. The shot cuts and it's on his shoulder and then cuts again and it's on his face again.
Continuity mistake: When Malcolm is throwing the dodgeballs at Stevie, the number of balls in the bag changes between shots.
Audio problem: You can hear the new boss speak, but her mouth doesn't move. (00:16:30)
Revealing mistake: When Lois confronts Susan about not telling her about Susan's kidney disease, Susan is telling Jamie how cute he looks in his sailor outfit. When the camera is moved to a different angle, it becomes very obvious that "Jamie" is just a prop baby doll. (00:11:10)
Continuity mistake: When Susan arrives Hal is holding Jaime, and the baby's entire body changes position between shots repeatedly - in some shots the front of Jaime's body faces Hal, yet in others Jaime's back faces Hal.
Experiment - S5-E18
Revealing mistake: In the first scene, Lois is feeding Jamie while talking to Dewey. In the next clip, it changes to just a prop baby doll toy with a beanie covering a majority of his face. (00:04:25)
Dewey's Special Class - S5-E19
Continuity mistake: When Hal and Craig dance on the Dance Dance Revolution arcade cabinets, in the long shots they are replaced by stunt doubles with obvious wigs worn. (00:05:00)
Visible crew/equipment: When Hal is walking the stroller with Jamie inside at the park and Hal approaches the Body Builders, the full body of a camera-man and the camera he's filming with is ridiculously visible on the right side of the screen in a wide-shot.
Pearl Harbor - S6-E4
Continuity mistake: Reese had a lot of food in his bowl (when complaining about the low-fat food she has made them eat), then Lois puts food in his suddenly empty bowl. (00:05:25)
Pearl Harbor - S6-E4
Continuity mistake: Lois and Jessica enter the house after coming back from going to a musical. As Lois comes through the door her purse slips off her shoulder and she catches it around her elbow. In the next shot a second later, the purse is back up on her shoulder. (00:16:00)
Kitty's Back - S6-E5
Visible crew/equipment: A hand is visible on the left edge of the screen when Francis is talking to Dewey through the bathroom door. (00:15:50)
Answer: It is made up - although it is implied she is Croatian, she never mentions it herself.