Nested Ditamap

Hi,

Can anyone tell me why, when I open a .ditamap file, it is placed inside another MAP element thus making it invalid? I have to move all my topicrefs from the original MAP to inside the new MAP and delete the old (now empty) MAP. Yet when I close/ open the ditamap again, the same thing happens.

Please see the screenshots below which illustrate this.

Thank you.

Graham Miller