Same Action, Different Number of XEvent (using XRecord)

I use XRECORD to watch the behavior of X applications, such as oowriter.

I found that even if I do the same action every time, the order and number of 
XEvent I received were different.

For instance, when I click a menu item, sometime it generates 3 CreateNotify events.
But sometime it just generate 2. The thing goes more different if the action is more
complicate.

I have following questions:
1. I found that the 3 or 2 CreateNotify events are exactly same, include the time.
   Then why not use ONE event instead? Or can application treats all repeated event
   as a single one?
2. Does every application DO GET the repeated events, or just because of my using 
   of XRECORD?

If anyone knows anything about XRecord and could shed some light on this I would 
appreciate it.

Thanks very much.