Context menu on QGraphicsWidget

In my application, I have two types of object. One is a field element, the other is a compound element. Composite elements can contain two or more field elements. Here is my composite element implementation.

#include "compositeitem.h"

CompositeItem::CompositeItem(QString id,QList<FieldItem *> _children)
{
   children = _children;
}

CompositeItem::~CompositeItem()
{
}

QRectF CompositeItem::boundingRect() const
{
 FieldItem *child;
     QRectF rect(0,0,0,0);
     foreach(child,children)
     {
        rect = rect.united(child->boundingRect());
     }
    return rect;
}

void CompositeItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,   QWidget *widget )
  {
   FieldItem *child;
   foreach(child,children)
   {
      child->paint(painter,option,widget);
   }
  }

  QSizeF CompositeItem::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
  {
   QSizeF itsSize(0,0);
   FieldItem *child;
   foreach(child,children)
   {
      // if its size empty set first child size to itsSize
      if(itsSize.isEmpty())
          itsSize = child->sizeHint(Qt::PreferredSize);
      else
      {
          QSizeF childSize = child->sizeHint(Qt::PreferredSize);
              if(itsSize.width() < childSize.width())
                  itsSize.setWidth(childSize.width());
              itsSize.setHeight(itsSize.height() + childSize.height());
      }
  }
  return itsSize;
     }

     void CompositeItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
     {
          qDebug()<<"Test";
     }

      

        
        
        
      

    

My first question is how to pass a context menu event to a specific child element?

The image above shows one of my possible building blocks.

If you look at the code above, you can see that I am typing "Test" when the context menu event occurs.

When I right-click on the line symbol, I see that the message "Test" is printed. But when I right click on the signal, the Test symbol is not printed and I want it to be printed.

My second question is what caused this behavior. How can I overcome this.