Sliding glass patio doors "crack in the window"

This is the type of door I am talking about.

http://m.homedepot.com/p/Stanley-Doors-72-in-x-80-in-Double-Sliding-Patio-Door-with-Prairie-Style-Internal-Grill-600002/205211867

There is a crack in the window. It won't close properly. That's why it's so cold in here.

By crack I mean that when I slide the door closed, the isn't still a tiny gap. The door doesn't close properly. How would you say that?

Is "crack in the window" correct?

Thanks