如何摆脱QDialog中的resize-handle？

setWindowFlags(windowFlags() | Qt::FramelessWindowHint);

bool MyDialog::event(QEvent *event)
{
    if (event->type() == QEvent::MouseButtonPress) {
        m_mousePressPos = static_cast<QMouseEvent*>(event)->globalPos();
    }
    return QDialog::event(event);
}

void MyDialog::mouseMoveEvent(QMouseEvent *event)
{
    if (event->buttons() & Qt::LeftButton) {
        move(pos() + (event->globalPos() - m_mousePressPos));
        m_mousePressPos = event->globalPos();
    }
    QDialog::mouseMoveEvent(event);
}