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 #0000FF)]
        RenderText {TEXT} at (14,14) size 356x28
          text run at (14,14) width 356: "Should see \"XX\" in a single red box."
      RenderBlock {DIV} at (0,80) size 784x56
        RenderBlock {DIV} at (0,0) size 784x56 [border: (2px solid #FF0000)]
          RenderText {TEXT} at (14,14) size 17x28
            text run at (14,14) width 17: "X"
          RenderText {TEXT} at (31,14) size 17x28
            text run at (31,14) width 17: "X"
selection is CARET:
start:      position 2 of child 1 {TEXT} of child 1 {DIV} of root {DIV}
upstream:   position 2 of child 1 {TEXT} of child 1 {DIV} of root {DIV}
downstream: position 0 of child 2 {TEXT} of child 1 {DIV} of root {DIV}
