First of all concerning your composite item's ::boudingRect(), you really should "think about it" My guess is to merge every child item's bounding rect.

To ensure you computed the right boundingRect, add this code in your CompositeItem:aint() :

Qt Code:
  1. painter->save() ;
  2. painter->setPen(Qt::yellow) ;
  3. painter->setBrush(Qt::NoBrush) ;
  4. painter->drawRect(boundinRect()) ;
  5. painter->restore() ;
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And try to right-click on your composite item, maybe it will suffice (didn't try so I'm not sure)