It has been my limited experience that AfterUpdate is more suited for combo boxes and the like. LostFocus seems to be more for areas where someone is going to be typing something in. Like I said, however, this has just been my experience. I recently used LostFocus for a textbox where it would convert all the text to UCase when the user was done typing something. Hasn't failed yet. Hopefully that statement didn't jinx me.
Jon