Layer tree when the fixed elements are out-of-view (should be blank):
Layer tree when the fixed elements are in-view (both fixed elements should have layers):
(GraphicsLayer
  (anchor 0.00 0.00)
  (bounds 800.00 600.00)
  (children 1
    (GraphicsLayer
      (bounds 800.00 600.00)
      (contentsOpaque 1)
      (children 2
        (GraphicsLayer
          (position 100.00 50.00)
          (bounds 10.00 10.00)
          (contentsOpaque 1)
        )
        (GraphicsLayer
          (position 100.00 100.00)
          (bounds 10.00 10.00)
          (contentsOpaque 1)
        )
      )
    )
  )
)
Layer tree when the fixed elements are out-of-view again (should be blank):