[iOS] `ScrollViewer.ManipulationDelta` not firing consistently (physical device) about uno HOT 4 OPEN

For context, this is used on our document viewer to pinch-to-zoom - the translate mode works for panning,

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Hey @brookslindseyjr thanks for teh report.

I've also attempted to wrap the ScrollViewer with a Grid and subscribe to the ManipulationDelta there with the same results.

Did you tried to put it inside the ScrollViewer instead?

I suspect the issue is that the native UIScrollView "stoles" the pointers when it thinks that you are starting to scroll (then all pointers are going native only and we don't receive them anymore). As events are bubbling from bottom to top, if you put you container within the UIScrollView (i.e. in the ScrollViewer) we will get events first and we are able to prevent such behavior.

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BTW, for a viewer, you can also just remove the ScrollViewer and only use manipulation events with a RenderTransform. The only down side is that you won't get the scroll-bars.

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With the element inside the scrollviewer, we receive the events as expected.

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