I am having a very strange problem with an OpenGL visualization in a Qt window. The basics of the application:
QMainWindow with a derived QTabWindow as the central widget. The first tab is for editing an XML input file and is another QMainWindow. The second tab is a QWidget containing a QGLWidget and some editing dialogs on the side.
The issue is with the QGLWidget -- it won't render the image. It is either completely blank or has random pixels from the desktop or other applications. The very strange thing is, it works perfectly on both my Macs and when I ssh (with X11 forwarding) onto a RedHat cluster. It is only happening on my Ubuntu laptop (14.04). I have tried building it with Qt4 and Qt5 without success, reinstalled them from Ubuntu's repository, tried again, and then installed the most recent Qt5 also without success. It's not a problem with OpenGL or X11 as far as I can tell because I can render another pure OpenGL/X11 visualization (i.e. it's not sitting in a Qt widget) without problems. I am getting no compiler warnings and no issues noted in the debugger.
I'm generally very competent with these things but this one has be stumped. If anyone has an idea or any suggestions about how diagnose the problem, I'd greatly appreciate it.