problem painting

[eric_vi]

within an MDI I have subwindows as QScrollArea with a QWidget scrollAreaWidgetContents inside

childScrollArea::childScrollArea(QWidget *parent) :
    QScrollArea(parent),
    m_ui(new Ui::childScrollArea)
{
 
        scrollAreaWidgetContents = new QWidget();
        childScrollArea->setWidget(scrollAreaWidgetContents);
 
        scrollAreaWidgetContents->show();
 
}
 
 
void childScrollArea::paintEvent(QPaintEvent * /* event */)
{
    QPainter painter(this);
 
    painter.fillRect(QRect(0, 0, 300, 300), Qt::blue );
}

childScrollArea::childScrollArea(QWidget *parent) :
    QScrollArea(parent),
    m_ui(new Ui::childScrollArea)
{
 
        scrollAreaWidgetContents = new QWidget();
        childScrollArea->setWidget(scrollAreaWidgetContents);
 
        scrollAreaWidgetContents->show();

}
 
 
void childScrollArea::paintEvent(QPaintEvent * /* event */)
{
    QPainter painter(this);
 
    painter.fillRect(QRect(0, 0, 300, 300), Qt::blue );
}

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unfortunately the paint event in this case does not do any painting in the window!

what do i do wrong?

Thanks for any hint