click left mouse button, window's position change

[chris_rookie]

CustomizeQWidget::CustomizeQWidget(QWidget *parent)
    : QDialog(parent)
{
    this -> setWindowFlags(Qt::FramelessWindowHint);
}

CustomizeQWidget::~CustomizeQWidget()
{
}

void CustomizeQWidget::paintEvent(QPaintEvent *)
{
    QStyleOption opt;
    opt.init(this);
    QPainter p(this);
    style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
}

void CustomizeQWidget::mousePressEvent(QMouseEvent *event)
{
    if(event->button() == Qt::LeftButton)
    {
        m_last_mouse_position = event->globalPos();
    }
}

void CustomizeQWidget::mouseMoveEvent(QMouseEvent *event)
{
    if (!event->buttons().testFlag(Qt::LeftButton))
            return;
    const QPoint position = pos() + event->globalPos() - m_last_mouse_position; //the position of mainfrmae + (current_mouse_position - last_mouse_position)
    move(position.x(), position.y());
    m_last_mouse_position = event->globalPos();
}

I written code like this. it removed system's Frame and can be dragged. But , When I clicking a QPushButton throw mouse left button, keep a little time, the windows's position got changed. How can I fix it.

[J.Hilk]

@chris_rookie
I would suggest, by defining an area where you want the mousePressEvent to be a valid starting point.

If pressed in that area set a bool/flag to true and only move, when that variable allows it ?

[chris_rookie]

@J-Hilk
I got you.
But there's many of button. I have to writte so much code to fix this issue.
Is there any better suggestions ^_^.
if not, I would do like this.