QGLWidget Sporadically fails to expand into layout

[grahamrow]

Greetings!

I'm working, for the moment, with a statically built Qt 5.2.1 on Linux. I've been getting a problem that I haven't seen on other versions or platforms. Every once in a while, when I launch my application, my main QGLWidget doesn't occupy it's horizontal container! I'm suspected an internal bug, but that's always what I expect when I'm largely clueless as to the cause.

Expected behavior:
!https://dl.dropboxusercontent.com/u/10789691/Correct.png(Correct!)!

Occasional behavior:
!https://dl.dropboxusercontent.com/u/10789691/Incorrect.png(incorrect!)!

The app responds perfectly after I resize the thing. I've tried a variety of manual resize(), update(), and other calls. Also I've tried reimplementing sizeHint() within my class. Are there any known problems here?

Thanks!
Graham