OK, I think we have all the rules for modifiers:
1) Modifiers can only appear in this order: Shift -- Option -- Control -- Alt
2) Modifiers are reserved words. You cannot have an Action named "Shift" or "Alt". You can have an Action named "ShiftAlt"
3) # is a reserved symbol, used as a delimiter between the modifier(s) and the Widget name, you cannot use "#" in your names.
That's it so far, hope we don't need any more rules
