I have a problem in migration from flex 3 to flex 4. I have two components, GenericView and GenericChartView. GenericChartView is a child of GenericView, it defines a chart component and it's implementation. When the state is "chart", we want to add the chart component to a component in it's parent, which is GenericView. In flex 3, we use addChild to do this function. But in flex4, it seems we can only move the chart component to it's parent, or move the parent stuff to it's child. Do we have an option to keep the current implementation of GenericView and GenericChartView, and when the state is "chart", add the chart component to it's parent?