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.
Revealing mistake: In the episode where Teri Hatcher's character is in the supermarket, as you see her place her two items, a carton of OJ and a carton of eggs, listen closely. The items are empty -- quite obviously so. (00:17:45)
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)
Continuity mistake: When Lynette is at the school, the teacher is waiting outside eating. If you look at her hands, you can see that she has a white napkin. The napkin changes from one hand to the other between shots, and in one shot it is small and the other it is not.
Continuity mistake: At one point in episode 1.2 ("Ah, But Underneath"), Susan looks at the note used to blackmail Mary Alice and we can see that it has been folded twice and become somewhat crumpled. Two episodes later in "Who's That Woman?" (1.4) when the girls show the note to Paul, it is almost perfectly smooth with a single horizontal crease.
Continuity mistake: When Bree goes to see Zak, in one shot her hands are intercrossed, then in the next her arms are crossed. (00:17:55)
Running to Stand Still - S1-E6
Continuity mistake: In one shot during the poker scene the baby moniter changes position to the other side of Lynette then back again. (00:13:30)
Running to Stand Still - S1-E6
Visible crew/equipment: When Susan is following Paul in the car she borrowed, we can see the reflection of a crew member on the right hand side of the window. (00:18:15)
Running to Stand Still - S1-E6
Continuity mistake: When Lynette is talking to Jordana the items on the table keep changing position in between shots. (00:29:30)
Running to Stand Still - S1-E6
Continuity mistake: When Bree goes over to talk to Dr. Goldfine in the restaurant, she puts her napkin on top of her plate, but when she sits back down, she takes it off of her chair.
Continuity mistake: When Bree sees the presents that Rex has bought for the children, she walks up to the car. As she stops walking you can see her hair particularly on her left side is being blown gently by the wind and continues to be blown through most of the shot. In the following shot her hair is now sitting perfectly without any wind blowing it.
Deliberate mistake: When Susan falls through the floorboards of Mike's house she uses the nearby towel to try and get the dog Bongo to help her. If you watch at the different angles the position of the dog keeps changing. When it shows Susan from behind the dog is almost right next to her face and stepping on the towel. In the shots from in front of Susan the dog is nowhere near the towel or even in the shot. This mistake looks more deliberate as the front on shots of Susan, the dog would likely have blocked her face from the camera.
Continuity mistake: When Bree, Susan and Lynette are scrubbing the road, a red sports car zooms past them. Lynette stands, hurls abuse and throws her scrubbing brush at the car which can be seen bouncing off the car and down the road. She then kneels down and continues to scrub with the brush.
Continuity mistake: As Susan tries to get the dog to help the second time you can see the towel Susan tried to use to get the dog to help her. The shot then shows Susan and the towel has disappeared. After a quick shot of the dog it cuts back to Susan and the towel has reappeared.
Plot hole: Several days must have passed between the teaser of this episode and the rest of it, since Gabrielle has had time to make up (very professional-looking) cards and posters, gotten several dozen volunteers and reserved dresses for many of them, yet Paul has only just gotten around to disposing of Mrs. Huber's body and trying to wash the blood out of his shirt. Even if we assume the teaser takes place right after the end of the last episode (when Paul murdered her), that's still several days of keeping a rotting corpse and enough evidence to put him away for life around his house.
Continuity mistake: When Bree gets out of the golf cart to see Rex on the field, she is carrying a pot of urine in her left hand, but in the next shot, of her upper torso and face, her left hand is clutching the strap of her handbag and the pot is now in her right hand.
Continuity mistake: When Lynette is sitting on the bench chatting to Claire in the park, you can see that Lynette has her hand on the pram, but when the camera angle is behind Lynette in other shots, she no longer does.
Answer: Kayla was sent away in episode 16 (The Gun Song) in season 4, after falsely accusing Lynette of child abuse. She now lives with her grandparents - probably Nora's parents.
I'm curious why we never see her again, why she never talked about, and why Tom never mentions visiting her.