T5: form zone parameter not taken into account

[Stephane Decleire]

I've got a form with a zone parameter but i still get the following 
warning and the whole page is refreshed when i submit the form. Any idea ?

[WARN] ComponentInstanceResultProcessor Component Test:accountmanagement 
was returned from an event handler method, but is not a page component. 
The page containing the component will render the client response.

Thanks in advance.

Stephane