連動するコンボボックス
よくあるよね。
県を選んで市を選ぶみたいな。
Relate Two ComboBoxes In Flex: My Example and Your Suggestions For Improvement
http://www.brucephillips.name/blog/index.cfm/2006/12/13/Relate-Two-ComboBoxes-In-Flex--My-Example-and-Your-Suggestions-For-Improvement