def each
      child_after = 0
      while (child_after = FindWindowEx(@parent.handle, child_after, nil, nil)) > 0 do
        window = Window.new child_after
        # immediate children only
        yield window if (window.parent) && (window.parent.handle == @parent.handle)
      end
    end
def each
      child_after = 0
      while (child_after = FindWindowEx(@parent.handle, child_after, nil, nil)) > 0 do
        window = Window.new child_after
        # immediate children only
        yield window if (window.parent) && (window.parent.handle == @parent.handle)
      end
    end
@param [Number] parent window handle

 @yield [Window]