Region not updated with QWS when a visible frameless window is deleted.

#include <QtGui>

class ChildWidget : public QWidget
{
    Q_OBJECT
public:
    ChildWidget(const QRect &rect, QWidget *parent = 0):QWidget(parent, Qt::FramelessWindowHint) {
	    setGeometry(rect);
	    QPushButton* pButton = new QPushButton("Test", this);
	    connect(pButton, SIGNAL(clicked()), this, SIGNAL(nextButtonClicked()));
	}

signals:
    void nextButtonClicked( );

};

class ParentWidget : public QWidget
{
    Q_OBJECT

public:
    explicit ParentWidget(QWidget *parent = 0);

public slots:
    void openChild( );

private slots:
    void childDestroyed(QObject*);

private:
    QLabel* movableLabel;
    bool posflag;

};

ParentWidget::ParentWidget(QWidget *parent) : QWidget(parent, Qt::FramelessWindowHint), posflag(true)
{
    setGeometry(45, 110, 150, 100);

    movableLabel = new QLabel(this);
    movableLabel->setGeometry(0, 0, 120, 150);

    QLabel *pLabel;
    QPushButton* pButton;

    pButton = new QPushButton(QString("0000"), movableLabel);
    pButton->setGeometry(20, 0, 50, 45 );

    pLabel = new QLabel(QString("0000"), movableLabel);
    pLabel->setGeometry(70 ,0, 120, 45 );

    pButton = new QPushButton(QString("1111"), movableLabel);
    pButton->setGeometry(20, 50, 50, 45 );

    pLabel = new QLabel(QString("1111"), movableLabel);
    pLabel->setGeometry(70 ,50, 120, 45 );

    pButton = new QPushButton(QString("2222"), movableLabel);
    pButton->setGeometry(20, 100, 50, 45 );

    pLabel = new QLabel(QString("2222"), movableLabel);
    pLabel->setGeometry(70 ,100, 120, 45 );

}

void ParentWidget::openChild( )
{
    posflag = !posflag;
    QRect childRect(84,  100 /* <-  less than 110 to reproduce  */ 
                    + (100*(posflag ? 1 : 0)), 150, 130);

    ChildWidget *child = new ChildWidget(childRect);
    child->show();

//  update();

    connect(child, SIGNAL(nextButtonClicked()), child, SLOT(deleteLater()));
    connect(child, SIGNAL(destroyed(QObject*)), this, SLOT(childDestroyed(QObject*)));
    connect(child, SIGNAL(destroyed(QObject*)), this, SLOT(openChild())); // reopen

}

void ParentWidget::childDestroyed(QObject*) {

    // toggle label position
    if(movableLabel->pos().y() == 0 ) {
        movableLabel->move(0,-100); // hide 0000 and 1111, show 2222
    } else {
        movableLabel->move(0,0);    // show 0000 and 1111, hide 2222
	}
}

int main( int argc, char *argv[] )
{
	QApplication app(argc, argv);

    ParentWidget w;
    w.show();
    w.openChild( );

    return app.exec();
}

#include "main.moc"