Continuity mistake: When Bree Van De Kamp is first shown with her muffins, we see that the hand towel on the right basket is not in her hand, then when the shot changes it is. (00:05:20)
Continuity mistake: When Lynette comes out of the pool, after getting her boys, she is wearing high heels, but when the shot changes to a distance, she isn't wearing anything on her feet. (00:13:15)
Continuity mistake: Season 1, episode 1 (Pilot): While Gaby and Carlos are arguing in their house, we can see a sofa and some other items in a semi-circular alcove with five tall windows on the far wall of the front room, and a painting near the stairs. A minute later, Carlos leaves and Gaby is alone with John, and the room has changed drastically. The alcove is now a flat wall with two windows and a fireplace. The sofa and some other things are missing and the painting moved to above the fireplace. This inconsistency exists because after the pilot was filmed, the set was redesigned and the part of John Rowland was recast. The scenes with John were reshot after the redesign took place, but the majority of this episode, including the first half of this scene (the argument), used the original footage. (00:17:30)
Continuity mistake: When Rex Van De Kamp is at the restaurant, his fork is half way over his napkin then in a later shot it's completely on the napkin. (00:26:50)
Continuity mistake: When Lynette is feeding her baby, we see from behind there is a backpack on her chair then when the shot changes it is not there. (00:29:55)
Continuity mistake: During the scene where Gaby and John are in her bedroom talking, she takes a drag from her cigarette while John asks why she isn't happy, but never exhales the smoke from that drag. 23 seconds pass from that drag to the next one and she's in frame the entire time (it cuts between shots of the two of them together and Gaby's close-ups, but doesn't cut away from her). It's also worth noting that Gaby is never seen smoking again at any other point in the series and no explanation is given as to why.
Continuity mistake: When Lynette is in the supermarket, right after she loses track of the twins, she is seen pushing her shopping cart down the aisle,and in the seat there's only a pink blanket. But when she sees Nelly Klein, her baby daughter is sitting in the seat with the blanket and one of her sons is riding in the basket.
Continuity mistake: In the restaurant, Bree makes a salad for Rex at the salad bar. It is fairly tall with lots of tomatoes. The salad she gives him is flatter and missing many of the tomatoes.
Continuity mistake: When we see Lynette driving her kids, in the first shot we see some red, blue and white decoration in the front of the car to the right, then when the shot changes it's in the centre. (00:13:50)
Continuity mistake: When Mike comes home with the shopping bag, we see that the items in his shopping bag change positions in between the shots when he goes to see Edie arrive. (00:20:30)
Continuity mistake: When Mike is taking his dog to the vet, we see that Susan's hair is covering her ear in all the shots except the last one when her hair is behind her ear to show that the earring is gone. (00:39:30)
Continuity mistake: When Julie is leaving we see that she leaves the door open and then it closes with a slight open gap, yet just for one shot the door is completely closed, then it's open again. (00:09:50)
Continuity mistake: When Lynette gives her husband his photo, the position of the photo changes in between shots. (00:13:05)
Continuity mistake: When Gabrielle and Carlos are saying hello to Ashley, the position of her hands change on the ball, from the front to the side to the front again. (00:14:40)
Continuity mistake: When Karl is speaking to Susan whilst she's in the towel, we see in one shot his chin is resting on his palm, then when the shot changes he tilts his head and then moves his fingers to his chin then when the shot changes his chin is resting on his palm again. (00:25:00)
Continuity mistake: When Bree steals Mary Alice's tape in Dr Goldstein's room, she takes it with her right hand and grabs it to her waist while she raises her left hand to her hair. In the next shot when the doctor enters the room, you can see her right hand is up, and when the camera comes on her the next shot, her left hand is up again.
Continuity mistake: When Susan and Mrs.Huber are together in the Supermarket the position of the egg box keeps changing in between shots on the conveyor belt. (00:18:00)
Continuity mistake: When Lynette and Gabrielle are talking to Paul, the boxes Gabrielle are holding change position between shots under her arms. (00:34:30)
Continuity mistake: When Andrew is talking to his mum, Bree, on his bed, we see him put the magazine down, yet in a later shot it is no longer there. (00:38:10)
Answer: He was investigating the lead not the case.