Dawn theme product detail page sometime show complementary product, sometime no show，why？

[Songxitong]

When I customzie the Dawn theme product detail page's complementary product block, if I choose product 1, then the design interface show the complementary product block, and if I choose product 2, then the design interface doesn't show the complementary product block, does anyone know why this happened? thank you in advance!

and I also have another question, does anyone know how to delete the product informaiton's media block, I delete all the product information's element, but It still show media info,  does anyone know how to modify code of main-product.liquid to realize this aim