I tested example 28 and it worked well. However, I want to create 2 cubes in the same workspace. I add one more object and image, and I called them object2 and image2. I can see 2 cubes, but my first cube become transparent in the view when the second cube serve as its background. Look like the enclosed photo
(orange one is the first). Anyone have idea to fix it? I don't want any transparent.