Also see this thread regarding the LostFocus:
Possible bug in Lost Focus when using access keys / hot keys Thread #711927 Message #711927

>Hi,
>
>>In my opinion LostFocus should be used to determine if the focus can be lost.
>
>Possible, but Lostfocus have another bug ( Thread #849791 ),
>and it not stop the lose of the focus.
>
>Fabio