QGrachphicsItem can not been hit

blueshake

I meet a strange issue about QGraphicsItem.
1.I define a custom Rect item which derive from QGraphicsItem and rewrite the boundingRect,shape,paint.

codes are as follows.

QRectF CameraRectangleItem::boundingRect() const
{
    qreal extra = 30.0;
    return QRectF(m_startPoint.x(),m_startPoint.y(),m_width,m_height)
    .normalized()
    .adjusted(-extra,-extra,extra,extra);
    //return QGraphicsRectItem::boundingRect();
}
QPainterPath CameraRectangleItem::shape() const
{
    QPainterPath path;
    path.addRect(m_startPoint.x(),m_startPoint.y(),m_width,m_height);
    return path;
}
void CameraRectangleItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QPen myPen;
    if(this->isSelected())
        myPen.setColor(QColor(0,0,184));
    else
        myPen.setColor(Qt::green);

    painter->setPen(myPen);
    painter->setBrush(Qt::transparent);
    painter->drawRect(m_startPoint.x(),m_startPoint.y(),m_width,m_height);
    if(this->m_isDrawFontState)
    {
        QFont font("宋体",20,QFont::Bold,false);

        painter->setFont(font);
        painter->drawText(m_startPoint.x(),
                          m_startPoint.y(),
                          MyString::intToString(this->m_index)+":"+MyString::intToString(this->m_actualMatchValue)+"/"+MyString::intToString(this->m_presetMatchValue));
    }
void CameraRectangleItem::updatePos(QPointF endPoint)
{
    m_width = endPoint.x() - m_startPoint.x();
    m_height = endPoint.y() - m_startPoint.y();
    //this->update(m_startPoint.x(),m_startPoint.y(),m_width,m_height);
}

2, in the scene,when the mouse press,add new item to scene,
3.when the mouse release, I call item's updatePos to update item's width and height.

it woke fine for the drawing the item.
here come the issue.
1.when I click the red zone as the picture shows. the item can not be hit.
Image 1.png
2.and then I click the black zone as the picture shows, the item is selected.
Image 2.png
3.in the step 2 , I move the item , and release the selection of the item.
at this time, when I click anywehre of the item ,as the picture shows, it can be hit
Image 3.png

any one has any idea on this ? thanks.