Steve,
Thank you for your answer.
I suppose that I'm not enough clear in my need, so your solution will not work in my case.It's not the frametext as i wrote before but only the frame with the std fields inside.
My Process:
Custom VA01 flavor
Add a new script button on the first screen
When I click on this one, I need to Hide the frame with PO fields (if the frame visible) or unhide (if the frame isn't visible).
Flo.