QQuickRenderControl disfunctional when having both a retina and non-retina screen connected

Possibly related to https://bugreports.qt.io/browse/QTBUG-42114

When I attempt to run the QQuickRenderControl example project in Qt Creator on my Macbook (with a built-in retina display) and with a 1920x1080 conventional external display attached, the cube appears as completely white. When I disconnect my external display, the cube renders as it does on my Windows machines.

This is on Qt 5.4.1

I'm working on another application which is attempting to take advantage of the control and which is failing in a slightly different manner. The application works if it's running on the normal monitor, but if I move it to the retina display, the QQuickRenderControl rendering results in a blank texture (0 in the alpha channel).

I was able to capture this in apitrace and I've put the trace file here: https://s3.amazonaws.com/Oculus/render-utils-tests.trace.gz

Specifically, you can see that frame 630 renders the test dialog correctly, but frame 632 does not.

The problem seems to stem from call 63015 in frame 632:

glViewport(0, 617, 808, 617)

The previous frame's equivalent call (62732 in frame 630) was

glViewport(0, 0, 808, 617)