There's one more important thing to understand about flows. If you run out of space horizontally, Shoes will never create a horizontal scroll bar. Instead, Shoes will create the elements lower down on the "next line" of the application. It's like when you reach the end of a line in a word processor. The word processor doesn't create a scrollbar and let you keep typing off the page, instead it places the words on the next line.
Shoes.app :width => 400, :height => 140 do
button "Button 1"
button "Button 2"
button "Button 3"
button "Button 4"
button "Button 5"
button "Button 6"
end
