Okay, I'm clearly doing something wrong, but I've created an Item, then linked several part files to it.  I checked the Item in.  I also created a Bill of Materials definition (Item BOM) and it shows up in the Bill of Materials tab in the Item Explorer.

All I see, though, is the Item itself.  The part I've added to the Item don't show up in the BOM tab, no matter what I do.  What might cause this?