Continuity mistake: Adam hands Katherine the note he found on the floor written by her aunt in a previous episode. Katherine is holding the paper up. When Adam walks around her in the next shot, the paper is gone and Katherine is only holding her keys/purse. The close up of Katherine (the very next shot) shows her holding the paper again.

Desperate Housewives (2004)
1 mistake in Welcome to Kanagawa
Bree Van De Kamp: It's the age-old question, isn't it? How much do we really want to know about our neighbours?
Trivia: Across Season 4: Two Lois Lanes appear together in this season: Teri Hatcher played Lois Lane in The Adventures of Lois and Clark and Dana Delaney voiced Lois Lane in Superman: The Animated Series and its follow-ups.
Question: Where did Kayla go? When did they get rid of her and where did she go? And which episode is it?
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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.