Hi Cliff! Thanks for an answer!
however, from adobe's documentation:
Navigator containers such as Accordion, TabNavigator, and ViewStack implement the ContainerCreationPolicy.AUTO policy by creating all their children immediately, but wait to create the deeper descendants of a child until it becomes the selected child of the navigator container
i.e. there is no point in listening a child's creationComplete event, rather we need to listen a child's child, this may be a code bloat... Could ViewStack's "change" event help?