AccumulatedVisualContext Tree:
  [1] scroll_frame_id=1 (PaintableWithLines(BlockContainer<PRE>#out))
    [2] clip=[8,8 100x100] (SVGForeignObjectPaintable(SVGForeignObjectBox<foreignObject>#fo))
      [3] clip=[8,8 100x100] (PaintableWithLines(BlockContainer(anonymous)))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x121]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x100]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x100]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 100x100]
  Save@2
    AddClipRect@2 rect=[-2,-2 119x119]
    SaveLayer@2
      ApplyEffects@3 opacity=1 has_filter=false
        PaintNestedDisplayList@3 rect=[-2,-2 119x119]
          Translate@0 delta=[2,2]
          FillPath@0 path_bounding_rect=[8,8 100x100]
      Restore@3
    Restore@3
  Restore@3
  Save@2
    AddClipRect@2 rect=[-2,-2 119x119]
    SaveLayer@2
      CompositorWheelHitTestTarget@2 target_scroll_frame_index=0 rect=[8,8 100x100]
      CompositorWheelHitTestTarget@3 target_scroll_frame_index=0 rect=[8,8 100x100]
      FillRect@3 rect=[8,8 100x100] color=rgb(0, 0, 0)
      ApplyEffects@2 opacity=1 has_filter=false
        PaintNestedDisplayList@2 rect=[-2,-2 119x119]
          Translate@0 delta=[2,2]
          FillPath@0 path_bounding_rect=[8,8 100x100]
      Restore@2
    Restore@2
  Restore@2
Restore@0