[Qt-interest] QGLWidget & QGraphicsView not repainting on 2nd Monitor

[Josiah Bryan]

Hey All -

I've got a QGraphicsView as the central widget in an app I'm working on. 
I setup OpenGL-accelerated painting using:

    graphicsView->setViewport(new QGLWidget(QGLFormat(QGL::SampleBuffers)));

Works great on Linux & Windows XP - no problem.....well, almost.

When I plug in a second monitor to my XP laptop and enable it, all of a 
sudden my app refuses to start (Window frame appears, but no UI response.)

Stepping thru it with the QtCreator debugger, it seems its caught in 
some sort of loop. So, I turn off the 2nd monitor and the app runs fine. 
With the app running, I plug in & enable 2nd monitor, then drag the app 
to the second monitor.

Bottom line is that any portion of the window on the 2nd monitor does 
not repaint, while the portion that remains on the primary monitor 
repaints just fine. (It's running various animations in the 
QGraphicsView, target is 15 - 25 fps.)

So, two problems - with 2nd monitor enabled, app refuses to start. If I 
disable monitor, start app, then enable monitor, app won't repaint on 
that monitor.

Any hints on how to debug or fix?

Thanks!
-josiah