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 784x56 [border: (2px solid #FF0000)]
        RenderInline {SPAN} at (0,0) size 157x28
          RenderText {TEXT} at (14,14) size 70x28
            text run at (14,14) width 70: "here is "
          RenderInline {I} at (0,0) size 44x28
            RenderText {TEXT} at (84,14) size 44x28
              text run at (84,14) width 44: "xxxx"
          RenderText {TEXT} at (128,14) size 43x28
            text run at (128,14) width 43: " text"
        RenderText {TEXT} at (0,0) size 0x0
selection is CARET:
start:      position 4 of child 1 {TEXT} of child 2 {I} of child 2 {SPAN} of root {DIV}
upstream:   position 4 of child 1 {TEXT} of child 2 {I} of child 2 {SPAN} of root {DIV}
downstream: position 0 of child 3 {TEXT} of child 2 {SPAN} of root {DIV}
