unexpected behavior of background method (_why fixed this already)

gistfile1.rbx

Shoes.app :width => 600, :height => 400 do
  flow :width => 400, :height => 400, :margin => 20 do    

    background white
    fill    '#dfd'
    stroke  '#ddd'
    rect    0, 0, 200, 200
    
  end
  background black
end

# works as expected: draws a window with a black background, then a white flow with a rectangle on top of it

gistfile2.rbx

Shoes.app :width => 600, :height => 400 do
  flow :width => 400, :height => 400, :margin => 20 do    
    
    fill    '#dfd'
    stroke  '#ddd'
    rect    0, 0, 200, 200
    background white

  end
  background black
end

# in this case draws a window with a black background, then a white flow WITHOUT any sign of the rectangle!