MACROMEDIA FLASH MX 2004-USING COMPONENTS Use Manual page 807

UIEventDispatcher.unload
Availability
Flash Player 6 (6.0 79.0).
Edition
Flash MX Professional 2004.
Usage
listenerObject = new Object();
listenerObject.unload = function(eventObject){
// insert your code here
}
componentInstance.addEventListener("unload", listenerObject)
Description
Event; broadcast to all registered listeners when a component is unloaded from Flash Player.
When the event is triggered, it automatically passes an event object (
handler. Each event object has properties that contain information about the event. You can use
these properties to write code that handles the event.
) to the
eventObject
UIEventDispatcher class 807