This just perplexes me, because no matter what I do I cant duplicate it. We will continue to investigate...
Don't you hate that! If you're like me, the solution will pop in your head in the middle of the night
Another idea just to eliminate people closing the workbook without using the BIG X or having to leave Full Screen to save - I would create 2 macro buttons on every page - SAVE and SAVE and EXIT. I don't use Excel much and when I first started testing the file I couldn't figure out how to save, so I clicked the BIG Red X so it would prompt me to save.
Although I love (and need) the full screen toggle, I would make it available maybe only on a separate options page. That button on every page invites you to click and makes it waaay too easy to mess things up. That way people that need it will find it, and those that don't won't click it.
Thanks again Scott and Hunter for this little gem of software. Have a great weekend!