macro toggle

I've got a very simple macro to switch on 'Navigation Pane' from view
menu:

Sub Nav()
'
' Nav Macro
' Macro recorded 6/20/08 by Robert Paulson
'
    ActiveWindow.Do***entMap = True
End Sub



Is there an easy way to make this toggle true/false so that I don't
have to record another macro to turn it off again?

thanks