Dress parade occurs before dress rehearsal, so that the director may see the costumes before the actors work in them.
true / false.

True

Explanation:

When I preformed in my musical we would get our costumes and go outside to she if she liked them. If she didn't agree with it then we were sent back to find another one. This is just preparation for the your play to make sure it fits properly and it would match in the scene you're in.