Ok I've solved my problem. I modified the reportbuilder.app and changed the ReportBuilder.ProcessEvent include in frxbuilder.prg to check if the value of the m.iEventType is 8 (which happen when I close the report) then I put a Alt-F4 in the keyboard buffer.

>Hi Marc,
>
>>Hi guys.
>>
>>I've created an external report designer and I would like to know how can I close the VFP screen if the user close the report with the File/Close menu or with the report X button ? Should I use a timer which will check for opened windows and close himself if no windows are opened or is there an easier way ?
>
>Would be Destroy event in DataEnvironment one way?
>Put something like "_Screen.Release()".
>P.S.: I dind't test it.
>Good luck!