I have a blank workbook open and then enable my Add-In via Tools/Add-Ins.
The Add-In does get "loaded" but the sheet I had open somehow gets closed.
Similarly, if my Add-In is loaded - and I double click on a workbook in the
Windows Explorer - the workbook does not get opened - Excel starts with no
workbook. However, doing File/Open will open it without problems. I can find
no code in my Add-In that looks like it would cause this. Can anyone point
me in some direction? Any help appreciated.

Steve