I don't know why, but with `WINDOW_AUTOSIZE` I get:
```
2014-02-13 00:13:59.275 cpp-example-qt_opengl[58149:507] invalid drawable
2014-02-13 00:13:59.288 cpp-example-qt_opengl[58149:507] invalid drawable
2014-02-13 00:13:59.320 cpp-example-qt_opengl[58149:507] invalid drawable
2014-02-13 00:13:59.321 cpp-example-qt_opengl[58149:507] invalid drawable
2014-02-13 00:13:59.373 cpp-example-qt_opengl[58149:507] invalid drawable
```