When QGraphicsView has a QGLWidget as its viewport, the background is not updated correctly when there is no scene

When QGraphicsView has a QGLWidget as its viewport, the background is not updated correctly when there is no scene, moving a window over it will cause artificats to be left on the view.

The following example demonstrates the problem:

#include <QtGui>
#include <QtOpenGL>
int main(int argc, char **argv)
{
QApplication a(argc, argv);
QGraphicsView gv;
gv.setViewport(new QGLWidget(&gv));
QGraphicsScene *s = new QGraphicsScene(&gv);
s->addRect(0, 0, 50, 50, QPen(Qt::blue), QBrush(Qt::blue));
gv.setScene(s);
gv.setBackgroundBrush(QBrush(Qt::red));
gv.show();
gv.setScene(0);
return a.exec();
}

Update: As a temporary workaround, you can assign an empty scene to the view instead of no scene (0).