Losing keypresses

[David Eastman]

It seems to be the case that if I have a program that captures key events 
and I push a button, the keypress events stop coming to the block.

Is there a way to refocus the keypress events back to the shoes app?
Shoes.app (:width => 300, :height => 200) {
  ..
  stack  {
   ..

     @but = button "Restart"

     @but.click {
       ..
     }

     keypress { |k|
       ..
     }

  }

}