QTableView background problem

[Roy44]

Hi,

I would like to draw a pixmap on bottom right corner of a QTableView.
For that I overrided the panit event function:

void MdTextureTableView::paintEvent(QPaintEvent* event)
{
    if(!m_pixBackground.isNull())
    {
        QPainter painter(viewport());
        int iHeight = viewport()->height() / 1.5;
        int iWidth = (m_pixBackground.size().width() / m_pixBackground.size().height()) * iHeight;
        painter.drawPixmap(viewport()->width() - iWidth, viewport()->height() - iHeight, iWidth,iHeight, m_pixBackground);
        painter.end();
    }
    QTableView::paintEvent(event);
}

I have this results (ok for me)

but when I scroll, I have this horrible results:

I don't know what I missed, how can I fix this ?
Even this does not change anything:

QObject::connect(horizontalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(repaint()));

More information:
(I set a QStyledItemDelegate to display elements)

[Roy44]

QObject::connect(horizontalScrollBar(), SIGNAL(valueChanged(int)), this->viewport(), SLOT(update()));