AccumulatedVisualContext Tree:
  [0] transform=[1,0,0,1,0,0] origin=(0,0) (ViewportPaintable(Viewport<#document>))
    [1] scroll (PaintableWithLines(BlockContainer<PRE>#out))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_node_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[0,0 800x41]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,8 784x20]
  CompositorWheelHitTestTarget@1 target_scroll_node_index=0 rect=[8,8 100x20]
  FillRect@1 rect=[8,8 1x16] color=rgb(0, 0, 0)
  FillPath@1 path_bounding_rect=[6,6 104x24]
Restore@0

