Thanks so much for your help!
I spend a while longer on the topic, learning more about the buffer&widgetGL and now blit texture. I got as far as this project > https://sourceforge.net/projects/opengl-blit/files/
But I cant figure out why the blit does not work. I can see that the frameObject has proper texture/render. But when I try to blit it I got nothing.
Any help would be great!