QDoubleSpinBox doesn't respect the widget's locale property

On a German system (decimal separator ','), this will continue to use the ',' separator even though it should use '.':

#include <QtGui>

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

QDoubleSpinBox spinBox;
spinBox.setLocale(QLocale::C);
spinBox.setMaximum(10000);
spinBox.show();
spinBox.setValue(1000.12);

return app.exec();
}

If the locale defines that thousand and decimal separators are the same, then this will in fact show neither.