AccumulatedVisualContext Tree:
  [1] scroll_frame_id=1 (PaintableWithLines(BlockContainer<PRE>#out))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x71]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x50]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x50]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 168.54688x50]
  FillRect@1 rect=[69,-17 47x100] color=rgba(61, 174, 233, 0.5)
  Save@1
    AddClipRect@1 rect=[8,-17 61x100]
    DrawGlyphRun@1 rect=[8,8 169x50] translation=[8,62.984375] color=rgb(0, 0, 0)
  Restore@1
  DrawLine@1 from=[8,70] to=[45,70] color=rgb(0, 0, 0) thickness=10
  DrawLine@1 from=[57,70] to=[67,70] color=rgb(0, 0, 0) thickness=10
  Save@1
    AddClipRect@1 rect=[69,-17 47x100]
    DrawGlyphRun@1 rect=[8,8 169x50] translation=[8,62.984375] color=rgb(0, 0, 0)
  Restore@1
  DrawLine@1 from=[109,70] to=[116,70] color=rgb(0, 0, 0) thickness=10
  Save@1
    AddClipRect@1 rect=[116,-17 111x100]
    DrawGlyphRun@1 rect=[8,8 169x50] translation=[8,62.984375] color=rgb(0, 0, 0)
  Restore@1
  DrawLine@1 from=[116,70] to=[153,70] color=rgb(0, 0, 0) thickness=10
  DrawLine@1 from=[165,70] to=[227,70] color=rgb(0, 0, 0) thickness=10
Restore@0