An element with a finished fill-forwards animation should not trigger backing store outside the viewport.

(GraphicsLayer
  (anchor 0.00 0.00)
  (bounds 785.00 1110.00)
  (backingStoreAttached 1)
  (children 1
    (GraphicsLayer
      (bounds 785.00 1110.00)
      (contentsOpaque 1)
      (backingStoreAttached 1)
      (children 1
        (GraphicsLayer
          (position 18.00 1010.00)
          (bounds 100.00 100.00)
          (contentsOpaque 1)
          (drawsContent 1)
          (backingStoreAttached 0)
          (transform [1.00 0.00 0.00 0.00] [0.00 1.00 0.00 0.00] [0.00 0.00 1.00 0.00] [100.00 0.00 0.00 1.00])
        )
      )
    )
  )
)
Some text here to force backing store.