If keeping Darts, you will need to seal up all the top screen with a glass pane or similar in order to reach necessary humidity levels. Do make sure your plants can handle the high humidity or they will rot.

The ExoTerra background has crevices and slots that can become a problem with small frogs like Darts. My recommendation would be to remove it and either use a decorative film outside the tank or create your own molded in background. Bill (deranged chipmunk) has a couple good threads that explain how to do that. Good luck !