background message system.

[gameline]

Hi everybody!
I have this script:

Spoiler

#-----------------------------------------------------------------------------
#  Window Message Rewrite by Mac
#=============================================================================
class Window_Message < Window_Selectable
  # Alias Message_Window initialize 
  alias message_window_init initialize
    def initialize
    message_window_init
      self.opacity = 0
      @message = Sprite.new
      @message.bitmap = RPG::Cache.picture('Message')
      @message.y = 0
      @message.x = 0
      @message.visible = self.visible
      @message.opacity = 255
    end
  # Alias Message_Window update 
  alias message_window_upda update
    def update
      message_window_upda
        @message.visible = self.visible
      end
      end

It's working well until you are teleports to a new map.
than it's disapear and you can't see it again.

so what i'm asking is if there is a better system or you can fix it?
Thank you!