Qt's optimized OpenGL context switching

Hi,

I have a question concerning Qt's optimized OpenGL context switching. I am currently working on an application that uses many QGLWidgets. Pbuffers were then added to do some offscreen rendering. However, I am running into problems when switching between the pbuffer's context and a QGLWidget context. So, I was wandering how Qt manages its OpenGL contexts? Is it doing some sort of OpenGL context caching? If so how does that work?

Thanks in advance,