[SOLVED] Surface video is not clean at all (QGraphicsScene/QGraphicsVideoItem/QGraphicsView)

[AlterX]

Hello,
so, I'm having problem of rubbish pieces of surface where is not shown video.
My code looks like this:
@
QGraphicsScene *scene = new QGraphicsScene(this);

videoItem = new QGraphicsVideoItem;
_graphicsView = new QGraphicsView(scene);
_graphicsView->setViewport(new QGLWidget);
scene->addItem(videoItem);
...
_graphicsView->fitInView(videoItem, Qt::KeepAspectRatio);
@

Video is shown correctly, but rubbish pixels (pieces of other apps) are shown outside video's aspectratio.

How can I clean all surface and not just where video takes place?

[AlterX]

Ok, I found the correct way and post it to help someone in the future:
@
((QGLWidget*)_graphicsView->viewport())->updateGL();
@

This call clean the opengl surface at all.