Hello Chip.

Nice to hear from you again after a looong time :-)

In your unsuccessful code, are you ever creating an
instance of Class1?
YES and only once for this.

Private Sub Workbook_Open()
Set App = New Class1
Set App.my_app = Application
End Sub
Yes this does the trick and I am shameful of not thinking
properly... Oh Friday lunchtime (Sydney time)... Go for a
pint of beer!

Thanks again. See ya around
---
Tetsuya