No airport found in bgl

[Stumpy]

I have been working around with an airport in fsx airport degin editor. This morning everything was fine, i continued where I left off by loading the bgl from yesterday. Now I try to open it and it comes up with "No airport found in this file" now I am certain there is because I was using the exact same bgl literally hours before.
Has anybody come across this?
Any ideas?
Thanks
James

Edit: after searching a bit I just found it saved a backup, and it opened. Lucky let off i suppose