AccumulatedVisualContext Tree:
  [1] scroll_frame_id=1 (PaintableWithLines(BlockContainer<PRE>#out))
    [2] clip=[0,0 200x200] (SVGPathPaintable(SVGGeometryBox<rect>))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x200]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x200]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x200]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 200x200]
  FillPath@2 path_bounding_rect=[10,10 100x100]
Restore@0