Subclassing QGraphicsItemGroup

Hi everyone

I have system that has classes derived from QGraphicsWidget. I manage derived class objects in layouts on QGraphicsScene. Now I need a compound item that contain two or more QGraphicsWidget in it and also I need to put that item inside my layout. So I choose QGraphicsItemGroup and write I class like this.

Code:

---

class CompositeItem:public QGraphicsItemGroup,public QGraphicsLayoutItem
{
   ...
};

---

I only implemented sizeHint function again.
When add CompositeItem instance to layout it does not shown.
What may cause this? Where I made wrong?