Possible reason, I don't see where you are adding the instance of the custom component:
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The most common reason you don't get a creationCOmplete is that the component is constantly invalidating itself. Maybe something in the layout changes a property that affects size which forces a new measure and layout pass.
Putting a breakpoint on LayoutManager.doPhaseInstantation can help you debug these kinds of problems
Flex SDK Developer
Adobe Systems Inc.
Yeah, I wasn't adding the component in the main section of code, I was adding it in the event handler. So the event never got fired because the component needed to get added first. Good thing to know!