Hi Debbie,
What version of PowerDesigner are you using?
Does this happen with a speciic model or any model? If a specific model, has it been upgraded from a previous version of PD? How many extended model definitions have been attached to the model?
I have only seen a similar problem when multiple XEM (or resource) files have been attached to a model and the XEMs have the same names for the extended attributes, stereotypes, etc.
In order to verify the issue, I needed to review both the model and the XEM file in an XML editor. I then checked that the Object in the model had the correct reference to the object in the XEM.
Anthony