could some one please tell me what lowerchild() does i thought it would move one item below the other making it no longer visible but it seams not
Check out the documentation here: https://developer.xamarin.com/api/member/Xamarin.Forms.Layout.LowerChild/p/Xamarin.Forms.View/
I think what it means is, the state of the element doesn't change, You will just reference the visual element as  instead of it's current enumerable value in the visual stack.
If you get two child views of an layout overlapping (relative view, absolute view, grid, stack layout with negative spacing, etc)
you can use this to put one control behind another both visually on the screen and in the child enumeration order for that layout.
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