Why QFrame does not resize on QgraphicsScene?

[Manuka]

Hi,

I have a QGraphicsScene to which I would like to add a QFrame. I'm doing so by calling the addWidget function of the QgraphicsScene class.
On the created QFrame I've added a grid layout which contains QGraphicsWidget classes.

Why the QFrame always keeps its size? If I have a small number of elements in the layout it fits well inside the QFrame but
as soon as I add too much elements the widgets go outside of the boundaries of the QFrame. (I can stell see them because the QGraphicsView scrolls but outside of the frame)

Actually my goal is the having a border around my grid layout.

Do you have any ideas?

Thanks