As far as I know you must plug it temporarily to one of the channel of the surface material (or to a temp material applied to the mesh/faces) because the UV editor is only looking up for the surface material slot of the shading group, ignoring the two others slots.By the way, how do I see textures of displacement maps in uv texture editor?
Note that MtI does manage one single UV set (the default one) at this time.
Not sure I am getting your question right, I always applied textures to the shaders and shaders to meshes or faces. Not specifically in that order though.[the] texture editor [...] seems the only way to apply file textures to meshes, is it?