selectionChanged signal is emitted when selection is not changed

#include <QtGui>

class Output : public QObject
{
    Q_OBJECT

    public slots:
    void selectionChanged(QItemSelection selected, QItemSelection deselected)
    {
        qDebug() << "selectionChanged";

        qDebug() << "selected:";
        foreach(QModelIndex index, selected.indexes())
            qDebug() << index.row() << index.column();

        qDebug() << "deselected:";
        foreach(QModelIndex index, deselected.indexes())
            qDebug() << index.row() << index.column();
    }
};

#include "main.moc"

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

    QStandardItemModel *pModel = new QStandardItemModel(1, 4);
    pModel->setData(pModel->index(0, 0), "Item 1");
    pModel->setData(pModel->index(0, 1), "Item 2");
    pModel->setData(pModel->index(0, 2), "Item 3");
    pModel->setData(pModel->index(0, 3), "Item 4");

    if(QStandardItem *pItem = pModel->item(0, 1))
    {
        pItem->setFlags(pItem->flags() ^ (Qt::ItemIsSelectable | Qt::ItemIsEditable));
        pModel->setItem(0, 1, pItem);
    }

    if(QStandardItem *pItem = pModel->item(0, 2))
    {
        pItem->setFlags(Qt::ItemIsEnabled);
        pModel->setItem(0, 2, pItem);
    }

    if(QStandardItem *pItem = pModel->item(0, 3))
    {
        pItem->setFlags(0);
        pModel->setItem(0, 3, pItem);
    }

    QTableView *pTableView = new QTableView(0);
    pTableView->setModel(pModel);
    pTableView->show();

    Output output;
    output.connect(pTableView->selectionModel(), SIGNAL(selectionChanged(QItemSelection,QItemSelection)), SLOT(selectionChanged(QItemSelection,QItemSelection)));

    return a.exec();
}