My concern is that the sub could end up processing sheets in a different book altogether. I can check this as I mentioned in my last message, although I suppose ActiveWindow.parent.name = WB.name is better than what I wrote (that's what you were trying to tell me wasn't it? Sorry, I sort of tangented off here).
I guess I'm satisfied knowing I can at least 'check' to see if the sheets are in the proper workbook, but not 100% since I can't enforce it...
or wait...
after WorkbookA.Activate, ActiveWindow.SelectedSheets could only refer to WorkbookA ...
I do believe this solves my problem. Just needed to talk through it--thanks Tony, thanks Combo!