1. How many visible instance of excel could be loaded simultaneously?
2. How many hidden instance of excel could be loaded simultaneously?
3. Can you think of situation where a hidden instance of an excel file might interfere with normal operation of excel files by user?
4. What problems could be expected if a file left open hidden? (one case I can think of is that if a user opens it manually, not knowing it is already open, it will open as read-only).
5. How we can close all hidden instances of excel file upon closing a form?