When I open a workbook, and go to the VB Editor, there is
a project for that workbook, right. Okay, when I close the
workbook, the project is also gone. But here's the strange
thing. I have one workbook that - each time I open it,
there is an additional project added in the VB Editor. So
if I open the workbook and close it, its project is still
in the list. If I open and close it again, there is two of
them. If I open and close it a third time, there is three.
The only way to get rid of them is close and reopen Excel.

What do you think this is?

tod