For now, the answer has become "Don't move this item to a hidden layer." Instead, I'm marking the layer as hidden by default before I place the XData, and that seems to be working fine. I'm not sure how the XData vanishes, but for now, this is working for me.
I'm still curious if anyone has any suggestions as to how the XData goes away.
Jerry
2010-10-06 16:10:45