layer at (0,0) size 800x600
  RenderView at (0,0) size 800x600
layer at (0,0) size 800x48
  RenderBlock {HTML} at (0,0) size 800x48
    RenderBody {BODY} at (8,16) size 784x16
      RenderBlock {P} at (0,0) size 784x16
        RenderText {#text} at (0,0) size 513x16
          text run at (0,0) width 513: "Try selecting some text in this document. It should be have a green background."
selection start: position 0 of child 0 {#text} of child 1 {P} of body
selection end:   position 79 of child 0 {#text} of child 1 {P} of body