Text rendering is broken

#include <QApplication>
#include <QPushButton>
#include <QVBoxLayout>
#include <QWidget>

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

	QWidget w;
	w.show();

	QPushButton b{QStringLiteral("Quit"), &w};
	QObject::connect(&b, &QPushButton::clicked, &a, &QCoreApplication::quit);

	QPushButton b1{QStringLiteral("Dummy"), &w};
	QVBoxLayout vbl{&w};
	vbl.addWidget(&b);
	vbl.addWidget(&b1);

	return a.exec();
}