Drawing artifacts on QTableWidget when moved or scrolled in QMdiArea

Consider the following:

A QTableWidget with a few rows and columns is added as a subwindow of a QMdiArea. The table widget is resized so that it has some whitespace beyond its last column.

The table widget is then moved partially off the MDI area so that the table's whitespace is not visible. If the table widget is moved or scrolled back into view, drawing artifcats occur in the table's whitespace, following the table's horizontal grid lines.

The following example reproduces the problem:

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

QMdiArea mdiArea;
QTableWidget *table = new QTableWidget(4, 4);

for (int row = 0; row < table->rowCount(); ++row) {
for (int column = 0; column < table->columnCount(); ++column)

{ table->setItem(row, column, new QTableWidgetItem(QString("%0 - %1").arg(row).arg(column))); }

}

mdiArea.addSubWindow(table);
mdiArea.show();

return app.exec();
}