You can see this behavior in the UIExplorer app’s
<ScrollView> example. Fling to initiate a scroll in an inner
ScrollView and fling again (before scrolling ends) to increase scroll momentum. Often times, this causes the scrolling to stop.
I haven’t had gone through all of the
ResponderEventPlugin code yet, but I’m seeing that when
ResponderEventPlugin.extractEvents is called, the
topLevelTargetID is sometimes incorrect.
The touches that unintentionally stop scrolling appear to be associated with the parent
ScrollView instead of the inner
ScrollView‘s content. I traced this down to
[self isDescendantOfView:JSResponder] is sometimes
YES. Forcing it to always return
NO fixes the issue, but I’m pretty sure that’s not the intention of this method 🙂