AccumulatedVisualContext Tree:
  [1] scroll_frame_id=1 (PaintableWithLines(BlockContainer<PRE>#out))
    [2] transform=[0.9848077,-0.17364818,0.17364818,0.9848077,0,0] origin=(48,48) (PaintableWithLines(BlockContainer<DIV>.box.left))
    [3] transform=[0.8,0,0,0.8,0,0] origin=(138,48) (PaintableWithLines(BlockContainer<DIV>.box.right))

DisplayList:
SaveLayer@0
  CompositorWheelHitTestTarget@0 target_scroll_frame_index=0 rect=[0,0 800x600]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x101]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x80]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[8,8 784x80]
  CompositorWheelHitTestTarget@2 target_scroll_frame_index=0 rect=[8,8 80x80]
  FillRect@2 rect=[8,8 80x80] color=rgb(255, 0, 0)
  DrawGlyphRun@2 rect=[8,8 15x18] translation=[8,21.796875] color=rgb(0, 0, 0)
  CompositorWheelHitTestTarget@3 target_scroll_frame_index=0 rect=[98,8 80x80]
  FillRect@3 rect=[98,8 80x80] color=rgb(0, 0, 255)
  DrawGlyphRun@3 rect=[98,8 10x18] translation=[98,21.796875] color=rgb(0, 0, 0)
Restore@0