The upholstery that covers the back of the rear seat has come away at the top. What is the best way to secure this backing to the back of the rear seat. When the top comes down, this backing gets in the way and gets bent over under the folded rear window.

 

Simple as double-sided Gorilla Tape??

 

Glue would be better than tape. You'll want to use an upholstery-quality or shoe repair-quality glue....