He is right. Just make sure you clean the tub area that's your gluing too really really. Also wipe it with alcohol to make sure no residue remains for other cleaners before reglueing.

Glue it using a continuous bead of a silicone caulk. Also run a bead on the sides inside of the shower where the track meets the shower. Let dry for 24 hours before use. A bunch says you can go sooner, but if it gets touched or anything you can disform the beads you've run or even bump the track back out of place as it's not fully cured.