Backface Culling Issue

Hello Everyone.

I have another question…
It seems like the 2.7a build does backface culling to all polygons. So if I’m for example working with a simple plane and export it to Unity the backface is gone. So that if I turn the camera around the plane it’s totally gone… Same is happening if I turn “textured solid” in Blender on.
But I didn’t activate backface culling (under shading in N toolbar) it’s something that’s always happening since I installed version 2.7a

Is that a known bug or something?
And what can I do against it?