initial:
  regions current: false
  viewport blocked: false
  blocking regions: 0
passive element listener:
  regions current: false
  viewport blocked: false
  blocking regions: 0
blocking element listener:
  regions current: true
  viewport blocked: false
  blocking regions: 1
removed element listener:
  regions current: false
  viewport blocked: false
  blocking regions: 0
blocking window listener:
  regions current: true
  viewport blocked: true
  blocking regions: 0
removed window listener:
  regions current: false
  viewport blocked: false
  blocking regions: 0
display list after blocking element listener:
AccumulatedVisualContext Tree:
  [1] scroll_frame_id=1 (PaintableWithLines(BlockContainer<PRE>#out))
    [2] clip=[0,0 200x200]
      [3] scroll_frame_id=2 (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 800x213]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=0 rect=[0,0 800x200]
  CompositorWheelHitTestTarget@1 target_scroll_frame_index=2 rect=[0,0 200x200]
  CompositorScrollNode@1 scroll_frame_index=2 parent_scroll_frame_index=0 scrollport_rect=[0,0 200x200] max_scroll_offset=[800,900] is_viewport=false
  CompositorWheelHitTestTarget@3 target_scroll_frame_index=2 rect=[0,0 100x100]
  CompositorBlockingWheelEventRegion@3 rect=[0,0 100x100]
  CompositorWheelHitTestTarget@3 target_scroll_frame_index=2 rect=[0,100 1000x1000]
  PaintScrollBar@1
  PaintScrollBar@1
Restore@0