QTableView: moving items from under a span will create painting problems

#include <QtGui>
int main(int argc, char *argv[])
{
        QApplication app(argc, argv);
        QTableWidget tw;
        tw.setColumnCount(3);
        tw.setRowCount(3);
        tw.setItem(1, 2, new QTableWidgetItem("painterror"));
        tw.setSpan(1, 1, 1, 2);
        tw.setSelectionMode(QAbstractItemView::SingleSelection);
        tw.horizontalHeader()->setMovable(true);
        tw.show();
        return app.exec();
}