Test overlap is rendered correctly when hovering over elements

Case 1, original layer tree:
(GraphicsLayer
  (bounds 800.00 600.00)
  (children 1
    (GraphicsLayer
      (bounds 800.00 600.00)
      (contentsOpaque 1)
      (drawsContent 1)
      (children 2
        (GraphicsLayer
          (position 8.00 8.00)
          (bounds 784.00 0.00)
        )
        (GraphicsLayer
          (children 2
            (GraphicsLayer
              (position 100.00 100.00)
              (bounds 100.00 100.00)
              (contentsOpaque 1)
            )
            (GraphicsLayer
              (position 180.00 180.00)
              (bounds 260.00 260.00)
              (drawsContent 1)
            )
          )
        )
      )
    )
  )
)
Case 2: hovering over the "middle" element (causes that div to become its own composited layer)
(GraphicsLayer
  (bounds 800.00 600.00)
  (children 1
    (GraphicsLayer
      (bounds 800.00 600.00)
      (contentsOpaque 1)
      (drawsContent 1)
      (children 3
        (GraphicsLayer
          (position 8.00 8.00)
          (bounds 784.00 0.00)
        )
        (GraphicsLayer
          (position 100.00 100.00)
          (bounds 100.00 100.00)
          (contentsOpaque 1)
        )
        (GraphicsLayer
          (children 2
            (GraphicsLayer
              (position 180.00 180.00)
              (bounds 100.00 100.00)
              (contentsOpaque 1)
            )
            (GraphicsLayer
              (position 260.00 260.00)
              (bounds 180.00 180.00)
              (drawsContent 1)
            )
          )
        )
      )
    )
  )
)
Case 3: hovering over the "middle2" element (causes that div to become its own composited layer)
(GraphicsLayer
  (bounds 800.00 600.00)
  (children 1
    (GraphicsLayer
      (bounds 800.00 600.00)
      (contentsOpaque 1)
      (drawsContent 1)
      (children 3
        (GraphicsLayer
          (position 8.00 8.00)
          (bounds 784.00 0.00)
        )
        (GraphicsLayer
          (children 2
            (GraphicsLayer
              (position 100.00 100.00)
              (bounds 100.00 100.00)
              (contentsOpaque 1)
            )
            (GraphicsLayer
              (position 180.00 180.00)
              (bounds 100.00 100.00)
              (drawsContent 1)
            )
          )
        )
        (GraphicsLayer
          (children 2
            (GraphicsLayer
              (position 260.00 260.00)
              (bounds 100.00 100.00)
              (contentsOpaque 1)
            )
            (GraphicsLayer
              (position 340.00 340.00)
              (bounds 100.00 100.00)
              (drawsContent 1)
            )
          )
        )
      )
    )
  )
)
Case 4: hovering over the "top" element (causes that div to become its own composited layer)
(GraphicsLayer
  (bounds 800.00 600.00)
  (children 1
    (GraphicsLayer
      (bounds 800.00 600.00)
      (contentsOpaque 1)
      (drawsContent 1)
      (children 3
        (GraphicsLayer
          (position 8.00 8.00)
          (bounds 784.00 0.00)
        )
        (GraphicsLayer
          (children 2
            (GraphicsLayer
              (position 100.00 100.00)
              (bounds 100.00 100.00)
              (contentsOpaque 1)
            )
            (GraphicsLayer
              (position 180.00 180.00)
              (bounds 180.00 180.00)
              (drawsContent 1)
            )
          )
        )
        (GraphicsLayer
          (position 340.00 340.00)
          (bounds 100.00 100.00)
          (contentsOpaque 1)
        )
      )
    )
  )
)
Case 5: back to situation in case 1
(GraphicsLayer
  (bounds 800.00 600.00)
  (children 1
    (GraphicsLayer
      (bounds 800.00 600.00)
      (contentsOpaque 1)
      (drawsContent 1)
      (children 2
        (GraphicsLayer
          (position 8.00 8.00)
          (bounds 784.00 0.00)
        )
        (GraphicsLayer
          (children 2
            (GraphicsLayer
              (position 100.00 100.00)
              (bounds 100.00 100.00)
              (contentsOpaque 1)
            )
            (GraphicsLayer
              (position 180.00 180.00)
              (bounds 260.00 260.00)
              (drawsContent 1)
            )
          )
        )
      )
    )
  )
)