Materials with no textures still sample textures

[Rastar]

I was trying to create some test spheres for shading experiments with no textures assigned, just fixed material colors. It seems they still use textures from some other material. E.g., if I create a new empty material in MyGame and assign it the diffuse+normal shader, it will show a concrete preview in the material editor. When creating a brush sphere in the introduction scene, assigning it the material and running the game, it is rendered using the tire material

[Josh]

If the shader is doing a texture lookup, whatever texture was last left in that slot will be used. This is the expected behavior. There are shaders that do not use any textures. See "default.shader".

[Rastar]

Mmh, OK, wasn't aware of that. Is that for performance reasons? Otherwise it would seem like an unnecesary duplication of shaders that are identical except for those texture lookup code lines.