content: sub main() 
      screen = CreateObject("roSGScreen")
      m.port = CreateObject("roMessagePort")
      screen.SetMessagePort(m.port)
      scene = screen.CreateScene("MainScene")
      screen.Show()
      ' screen.SetScene(scene)
      
      while true
          msg = wait(0, m.port)
          if type(msg) = "roSGScreenEvent" then
              if msg.isScreenClosed() then
              end if
          end if
      end while
  end sub
  