How to restart original material in sketchup/vray


after downloading the soap model with its texture i tried to apply dirt map in diffuse slot in vray.
After doing so the oryginal bitmap of the soap is somwhere gone.

  1. Why i sketchup materials box - this material is only visible in a form of miniature box and the software does not show where it is in categories. It also is innactive - you can not see the details like with the rest of the materials - see the place of the texture on your hard drive?

  2. is it any option to restart or go back to the oryginal material before changes of bitmaps in vray asset editor? its a pain that after you apply some bitmaps and your oryginal texture is gone you can not go back to the oryginal material. i can not imagine why with the profesional software chaos grioup made such a bug