QGraphicsView stop drawing objects when a glwidget with GLVersion>3.1 set as viewport

[raziel]

When I create a QGLWidget with a custom GLFormat and set that widget as viewport of a qgraphicsview, if the glformat is higher than 3.1, the graphicsview stop drawing graphicsobjects or graphicsitems.

example( if I setVersion(3,1) the img pixmap is drawn, if I setVersion(3,3) the img pixmap doesn't appear in the scene):

QGLFormat glFormat;
	glFormat.setVersion(3,1);
        //glFormat.setVersion(3,3);
	glFormat.setProfile(QGLFormat::CoreProfile);
	glFormat.setOption(QGL::DoubleBuffer);
	glFormat.setOption(QGL::DepthBuffer);
	glFormat.setOption(QGL::Rgba);
	QGLWidget* widget = new QGLWidget(glFormat);
        QGraphicsView *graphicsView = new QGraphicsView();
        QGraphicsScene *scene = new QGraphicsScene();
	QGraphicsPixmapItem *img = new QGraphicsPixmapItem(QPixmap("btn-easy.png"));
	img->setPos(100,100);
	scene->addItem(img);
	graphicsView->setViewport(widget);
        graphicsView->setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
	graphicsView->setScene(scene);

QGLFormat glFormat;
	glFormat.setVersion(3,1);
        //glFormat.setVersion(3,3);
	glFormat.setProfile(QGLFormat::CoreProfile);
	glFormat.setOption(QGL::DoubleBuffer);
	glFormat.setOption(QGL::DepthBuffer);
	glFormat.setOption(QGL::Rgba);
	QGLWidget* widget = new QGLWidget(glFormat);
        QGraphicsView *graphicsView = new QGraphicsView();
        QGraphicsScene *scene = new QGraphicsScene();
	QGraphicsPixmapItem *img = new QGraphicsPixmapItem(QPixmap("btn-easy.png"));
	img->setPos(100,100);
	scene->addItem(img);
	graphicsView->setViewport(widget);
        graphicsView->setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
	graphicsView->setScene(scene);

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Any idea if it can be fixed? Or something that I'm doing wrong?

I was using the http://doc.qt.digia.com/qq/qq26-openglcanvas.html openglcanvas approach to draw transparent items on top of a GLWidget. But since my custom GLWidget (it happens with default QGLWidget like on the example) requires OpenGL higher than 3.1 (actually should be 4.x), I cannot keep this approach.

Anyone know another efficient approach to draw transparent widgets on top of a QGLWidget or how to set a graphicview viewport with a qglwidget using glcontext 4.x?
QT5 handles the graphic pipeline differently from the QT4 , can QT5 be a solution? Did anyone successfully made an openGLCanvas on QT5?

Thanks in advance.