AccumulatedVisualContext Tree:
  [1] scroll_frame_id=1 (PaintableWithLines(BlockContainer<PRE>#out))
    [2] clip=[10,10 200x150]
      [3] scroll_frame_id=2 (PaintableWithLines(BlockContainer(anonymous)))
        [4] clip=[11,11 300x100]
          [5] scroll_frame_id=3 (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 800x175]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x154]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=2 rect=[8,8 204x154]
  CompositorScrollNode@1 scroll_frame_index=2 parent_scroll_frame_index=0 scrollport_rect=[10,10 200x150] max_scroll_offset=[102,0] is_viewport=false
  FillPath@1 path_bounding_rect=[8,8 204x154]
  CompositorWheelHitTestTarget@3 target_scroll_frame_index=3 rect=[10,10 302x102]
  CompositorScrollNode@3 scroll_frame_index=3 parent_scroll_frame_index=2 scrollport_rect=[11,11 300x100] max_scroll_offset=[100,0] is_viewport=false
  FillRect@3 rect=[10,10 302x102] color=rgb(255, 255, 224)
  FillPath@3 path_bounding_rect=[10,10 302x102]
  CompositorWheelHitTestTarget@5 target_scroll_frame_index=3 rect=[11,11 400x80]
  FillRect@5 rect=[11,11 400x80] color=rgb(240, 128, 128)
  DrawGlyphRun@5 rect=[11,11 178x18] translation=[11,24.796875] color=rgb(0, 0, 0)
  PaintScrollBar@3
  PaintScrollBar@1
Restore@0