Viewport <#document> at (0,0) content-size 800x600 children: not-inline
BlockContainer <html> at (0,0) content-size 800x125 [BFC] children: not-inline
BlockContainer <body> at (8,8) content-size 784x109 children: not-inline
BlockContainer <div.upper> at (8,8) content-size 784x17 children: inline
frag 0 from TextNode start: 0, length: 5, rect: [8,8 46.15625x17] baseline: 13.296875
"upper"
TextNode <#text>
BlockContainer <div.mystery> at (8,100) content-size 784x0 children: not-inline
BlockContainer <div.lower> at (8,100) content-size 784x17 children: inline
frag 0 from TextNode start: 0, length: 5, rect: [8,100 43.359375x17] baseline: 13.296875
"lower"
TextNode <#text>
ViewportPaintable (Viewport<#document>) [0,0 800x600]
PaintableWithLines (BlockContainer<HTML>) [0,0 800x125]
PaintableWithLines (BlockContainer<BODY>) [8,8 784x109]
PaintableWithLines (BlockContainer<DIV>.upper) [8,8 784x17]
TextPaintable (TextNode<#text>)
PaintableWithLines (BlockContainer<DIV>.mystery) [8,100 784x0]
PaintableWithLines (BlockContainer<DIV>.lower) [8,100 784x17]
TextPaintable (TextNode<#text>)