All these QGraphicsItem, I have bundled in QGraphicsItemGroup.
I have a Search feature, which takes name of symbol and search it in view and once found highlihgt that symbol.
I have a zoom in feature, which zoomed in the view with pre defined scale.

Issue :

1. When I search symbol, except symbol's arc, all the part gets highlighted.
2. When I zoom in, arc of symbol gets disappear.

Here are screen shots :

Original symbol

After search, whole symbol should get highlight, but here arc is not getting highlighted.

After zoom in, arc is getting disappear

Code :
In searchSymbol feature, there is a function to highlight symbol.

class myGroup : public QGraphicsItemGroup
class myArc: public QGraphicsPathItem
class myLine: public QGraphicsLineItem 
class myEllipse: public QGraphicsEllipseItem

void myViewer::HighLightSymbol(QGraphicsItemGroup* symAddress)
{
    QList<QGraphicsItem*> childItems = symAddress->childItems();
    QPen mPen(Qt::SolidLine);
    mPen.setWidth(2);
    foreach (QGraphicsItem* chItem, childItems) {
       
      //if (myArc* poly = dynamic_cast<myArc*>(chItem))
        if (QGraphicsPathItem* poly = dynamic_cast<QGraphicsPathItem*>(chItem)) {
            qDebug()<<"HighLightSymbol Arc ----> "<<poly;
            poly->setPen(mPen);
        } else {
            if (myLine* line = dynamic_cast<myLine*>(chItem)) {
                qDebug()<<"HighLightSymbol line ----> "<<line;
                line->setPen(mPen);
            } else {
                if (myEllipse* ell = dynamic_cast<myEllipse*>(chItem)) 
                    ell->setPen(mPen);
            }
        }
    }
}

In above code, I have printed all the QGraphicsPathItem* poly and myLine* line. There address is exactly same as when symbol has created.

I know it is very difficult to guess issue from limited code. But still, if anyone has any suggestion, please provide it so atleast I will get some idea to debug.