content: sub Main()
      screen = createObject("roSGScreen")
      m.port = createObject("roMessagePort")
      screen.setMessagePort(m.port)
      scene = screen.CreateScene("MainScene")
      screen.show()
      scene.setFocus(true)
    
      while true
        msg = wait(0, m.port)
        msgType = type(msg)
    
        if msgType = "roSGScreenEvent" then
          if msg.isScreenClosed() then
            return
          end if
        end if
      end while
    end sub