真正的事件dispatch者是event.target,監聽事件（addEventListner）的對象是event.currentTarget，Flex skd中有言曰：
"Event objects also have target properties that reference the actual object which dispatched the event. In some cases, the target may not be the object for which you have registered a listener. This can occur when the object for which you have registered a listener contains a child component that also dispatches the same event (and
the event bubbles). If you want to ensure that you are getting a reference to the object for which the listener is registered to listen for the event, use the currentTarget property"
例：如爲容器mc1創建了一個同類型（或者說擁有相同事件）的子容器mc2，再爲mc1註冊click事件監聽器，當單擊子容器mc2時，則event.target指事件dispatch者mc2，而event.currentTarget指當前的事件處理者mc1，因此在使用時如果是要獲取被註冊事件監聽器的對象（一般都是如此）則用event.currentTarget，currentTarget屬性應具備兩條件，一是它註冊了偵聽器，二是正在處理事件。
"Event objects also have target properties that reference the actual object which dispatched the event. In some cases, the target may not be the object for which you have registered a listener. This can occur when the object for which you have registered a listener contains a child component that also dispatches the same event (and
the event bubbles). If you want to ensure that you are getting a reference to the object for which the listener is registered to listen for the event, use the currentTarget property"
例：如爲容器mc1創建了一個同類型（或者說擁有相同事件）的子容器mc2，再爲mc1註冊click事件監聽器，當單擊子容器mc2時，則event.target指事件dispatch者mc2，而event.currentTarget指當前的事件處理者mc1，因此在使用時如果是要獲取被註冊事件監聽器的對象（一般都是如此）則用event.currentTarget，currentTarget屬性應具備兩條件，一是它註冊了偵聽器，二是正在處理事件。
