Combobox changing event

[mark goldin <ma...@gmail.com>]

My combobox is acting strange, I think. I am listening to changing event
where I am refusing new items using the following code:
if (event.target.selectedIndex == -3)
{
event.preventDefault();
}
It works fine, no problems. The problem I am having is for a reason that I
am trying to find for the last few days some combobox instances when I move
away from the control and a new item was refused clicking again on the
combo will trigger changing event, but not all instances are doing it. Any
idea why would changing event fire when a focus is returned back to a
combobox after a new item was rejected?

Thanks