Endless summed it up pretty well. I'd call your example a coding error. I usually give my last button, when it's something like "Close" or "Cancel", an ID of 9. Then if I add or remove a button later in development I don't have to renumber everything and my buttons don't necessarily end up with consecutive IDs. Admittedly it can be a pain when using SetFocusedMenuItem() since there's no way to retrieve the index of a button given its ID, so that part of the code has to be adjusted when a button is added or removed.
-JT
