I have used the Alpha 5 unstable version, but I decided to start using the release version. That is Alpha 5, 0.1.0 (release 150).

I've gone back to the unstable version after this happened

GFX Card: AMD Radeon HD 7900 Series (4.4.12874 Compatibility Profile Context 14.100.0.0)

Running at max graphic settings with Fast Selection Effect and Ambient Occlusion.