I've encountered a lot of issues on Windows XP with QT/Angle but also quite a lot on Windows Vista/7 where the graphic drivers by default don't support properly OpenGL or pretend they do but don't answer properly to Qt's requests. This ended up with a big chunk of my users having a blank window or even no window displayed to them and no way to reliably detect this on our end.<p>This feature has been in the works for multiple months now and I'm really glad to finally see it ship officially with Qt 5.4, so congrats to the team!