Simple stack example misbehaving?

[Michael Saelee]

Hi folks,

I just started working through examples in the Shoes manual, and am  
trying:

Shoes.app do
  stack :width => 200, :height => 200 do
    background red
    hover { clear { background blue } }
    leave { clear { background red  } }
  end
end

As I understand it, the (initially red) stack should turn its  
background blue on mouse entry, then turn red again when the cursor  
leaves.  When I test it, however, the entire app window turns blue on  
entry, and I can't get it to turn red again.  Am I doing something  
wrong, not getting how it's supposed to work, or is this a bug?

I'm running Shoes 0.r1091 on a PowerPC (OS X 10.5.5).

Thanks,

- Michael