# File vtk/gtk/GtkGLExtVTKRenderWindow.rb, line 126
  def OnRealize(wid, event)
    if !@Created
      # you can't get the xid without the window being realized.
      realize
      if Config::CONFIG["host_os"] =~ /win32/
#        win_id = @widget.window.handle.to_s
        win_id = window.handle.to_s
      else
#        win_id = @widget.window.xid.to_s
        win_id = window.xid.to_s
      end
      @RenderWindow.SetWindowInfo(win_id)
      @Created = true
    end
    return true
  end