Texture not visible in material preview I've assigned material with textures and it displays properly in viewport, however, material preview still doesn't show my texture: 



Same thing in Material tab, the texture doesn't show, it's only a white sphere. Am i missing something?
BTW. Why to assign material, we must enter the Edit mode? It's problematic when assigning material to many different objects. Or maybe again i'm missing something here? :)

Blender file:
The texture is setup correctly, but you have mirror enabled with reflectivity set to 1. This means that the material is entirely reflecting the environment around it, but as the mirror color is black, no light is actually reflected.

If you disable mirror, the texture is visible:



Note that I also set the specular intensity to 0, otherwise the texture is a little difficult to see (but visible).