That's impossible. No one knows exactly what would be 'default' behaviour (in details) in some particular situation :-).
People writing tech docs are not better than us.

>Hi Edward,
>
>And I think that the incidents of "anytime you see something strange" would be decreased if the documentation cared to tell us just what the "default" (internal) behaviour was for each method/event.
>
>Cheers,
>
>Jim N
>
>>>Hello,
>>>I don't know, in which cases the function NODEFAULT is used. Can anyone tell me when this function is helpful?
>>>Thanks in advance
>>
>>NODEFAULT is used anytime you see something strange :-). Theoretical definition is that NODEFAULT suppresses base class behaviour, which is actually means some code hidden behind the scene. The most common example: when you finish typing in textbox the focus automatically moves to the next (by tab order) controls. But you did not write code to invoke this behaviour, correct? This is exactly 'hidden'/'internal'/'base class' code. So, if you want instead to move to another controls, then it's safe to say in this control lostfocus event:
>>Thisform.AnotherControl.Setfocus
>>NODEFAULT