Hi!
I want clone selected item at QGraphicsScene if user start moving item with pressed Alt.
I wrote this code:
Qt Code: 
  1. if(mouseEvent->modifiers() == Qt::AltModifier)
  2. {
  3. 	QList<QGraphicsItem *> itList = this->selectedItems();
  4. 	if(itList.size()==1)
  5. 	{
  6. 		DiagramElement *de = (DiagramElement*)itList[0];
  7. 		DiagramElement *declone = de->clone();
  8.  
  9. 		de->setSelected(false);
  10.  
  11. 		declone->setPos(mouseEvent->scenePos());
  12. 		this->addItem(declone);
  13.  
  14. 		declone->setSelected(true);
  15. 	}
  16. 	QGraphicsScene::mouseMoveEvent(mouseEvent);
  17. }
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This code is in class-child of QGraphicsScene. DiagramElement is child of QGraphicsItem.
After cloning old and new items are selected and moving together.
Old item is to stay in place and not be selected.