I have had this problem for awhile now and figured it's time to ask a question.
Imagine you have a Scroller on the screen, a PopUp in the systemManager's global coords. What is the correct way to track theScroller content with a popup as the v & h scroll position of the Scroller's bars change positions?
I have tried using the propertyChange event and listeneing for "verticalScrollPosition" and "horizontalScrollPosition" but when doing this, the popup always seems like it's a frame behind and never really syncs to the content in the scroller that I am outlining (1 - 5 pixels off in the direction scrolled).
I have also tried using callLater, UPDATE_COMPLETE event on the parent, everything I have tried renders incorrectly.
I'm also using the globalToLocal() point convertion, would this have anything to do with it? Would the scrollRect being set on the IViewport have something to do with the latency?