I worked on quite a large Flex3, Flash9 project but then dropped out of Flex/AS3 for a couple of years. Now I'm finding it a little confusing getting to grips with how things work in Flex 4, especially this whole Spark thing. My main use of Flex is for real-time applications like games (main project before was www.mydinos.com) where we used a Canvas.
One problem we faced was Canvas.addChild() only accepted IUIComponents. Now there are classes like SpriteVisualElement and Group and interfaces like IVisualElement... in fact the whole concept of 'elements' appears new.
Can anyone point me to a good summary of the changes, and new way of working, preferably aimed at Flex3 developers rather than starting from scratch? It appears that the new approach reduces overhead of doing real-time stuff, but I've not found a single overview, only lots of livedocs pages with brief 'don't use this anymore' comments.