layer at (0,0) size 800x600
  RenderCanvas at (0,0) size 800x600
layer at (0,0) size 800x600
  RenderBlock {HTML} at (0,0) size 800x600
    RenderBody {BODY} at (8,8) size 784x584
      RenderBlock {DIV} at (0,0) size 784x112 [border: (2px solid #FF0000)]
        RenderBlock {DIV} at (14,14) size 756x28
          RenderInline {B} at (0,0) size 36x28
            RenderText {TEXT} at (0,0) size 36x28
              text run at (0,0) width 36: "one"
        RenderBlock {DIV} at (14,42) size 756x28
          RenderInline {B} at (0,0) size 54x28
            RenderText {TEXT} at (0,0) size 54x28
              text run at (0,0) width 54: "three"
        RenderBlock {DIV} at (14,70) size 756x28
          RenderInline {I} at (0,0) size 40x28
            RenderText {TEXT} at (0,0) size 40x28
              text run at (0,0) width 40: "four"
selection is CARET:
start:      position 3 of child 1 {TEXT} of child 1 {B} of child 2 {DIV} of root {DIV}
upstream:   position 3 of child 1 {TEXT} of child 1 {B} of child 2 {DIV} of root {DIV}
downstream: position 3 of child 1 {TEXT} of child 1 {B} of child 2 {DIV} of root {DIV}