Flat pattern not correct when flat

Hello,

I have created the sheet metal part below using a single line sketch and Base-Flange feature.

The problem I am having is that when I try to flatten the part it is missing the top section of the part.

The first screen shot shows the part before it is flattened and the second is after.

Any help with this would be appreciated.

Cheers

Glenn

SolidworksSheet Metal