+3  A: 

You should set a breakpoint in the resizeGL method, and check the call stack, to see, in both cases, what was the reason for calling resizeGL. From code you provided, it is not obvious.

Cătălin Pitiș
Yeah... it looks like the layout hasn't finished initializing (see screenies). Well that's just dumb. Oh well... it's not a huge issue. Just means my graphics aren't quite centered.
Mark