When I export block from WED to MED with only one texture, all the textures in the WAD file are copied with it and are visible in the skins form, not the only one on the block. Is this the normal procedure?

I think,it is wanted by the following reason: If you import a mapentity,it would be very angry,if not all textures were required.You had to skin it again.In the new version you can apply the skin to the right texture and after that you can delete the not needed textures.Its the same,if you load a entity by merge.Sorry for my bad english!

Thanks for your answer, but I don't understand what you mean.