Hi everybody, I'm using Qt 5.4 and it seems prepareGeometryChange doesn't work correctly!!

I create a RouteItem inherit from qgraphicsobject include some lines and some nodes ( Node is another qgraphicsitems with fixed boundingrect ). when I move my nodes or change scale of my scene the RouteItem's shape changed and I call the prepareGeometryChange function of qgraphicsitem.

Everything looks OK I can select my item or right click on it, but strange problem happened when I want to delete one RouteItem, program crashed on the QGraphicsSceneFindItemBsbTreeVisitor::visit ??

this is my deletion code
Qt Code: 
  1. void RouteItem::deleteRoute()
  2. {
  3.       prepareGeometryChange(); // add if I forgot to call it before
  4.       m_parentScene->update(); // add this line for taking effect of prepareGeometryChange and recalculate items boundry
  5.       m_parentScene->removeItem(this);
  6.       deleteLater();
  7. }
  8.  
  9. RoteItem::~RouteItem()
  10. {
  11.       foreach(Waypoint* nd, nodeList) {
  12.              m_parentScene->removeItem(nd);
  13.              nd->deleteLater();
  14.       }
  15. }
  16.  
  17. QPainterPath shape() const
  18. {
  19.         QPainterPathStrocker strocker;
  20.         //  read all nodes calculate some geographical equations and create a path from items positions
  21.         return strocker.createStroke(path);
  22. }
  23.  
  24. QRectF boundingRect() const 
  25. {
  26.        if(nodeList.count())
  27.              return shape().boundingRect();
  28.        return QRectF();
  29. }
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thanks in advance.