Tablet example not working

I've just downloaded Qt 5.1.0 for Windows 64-bit (VS 2012, 525 MB) and built the tablet example. On Windows 8 x64, using an Intuos Touch 5 M, I can't paint in the canvas at all (independent of whether I use the tablet pen or touch). I tried both Debug and Release builds.

I also can't click on items in the Qt Creator window using the tablet pen. Everything is set up correctly and works in other applications (e.g. Photoshop CC)