>>
>>If it is for debugging purposes, then set a breakpoint "when expression changes".
>>
>
>No, it is for call a Business object method for update a field in the interface tier

I'm not sure about what are you really trying to do. And maybe I'm not the only one. 8-)

Try to explain the functionality you want, not going into the implementation details. If this is a navigational issue, then I don't get why do you need to detect that something changes if that change is actually produced by a user action. 8-S