When you say it's leaking, is it coming into the car or are you referring to water in the trough around the opening that's exposed when you fully open the roof? To some degree, there will be a little seepage getting around the glass portion and into that trough, and the trough is drained by tubes running behind the trim work to let it drain. Take a look at the trough and see if you see the drains, maybe let a little water run into those holes using a bottle or some container that will let you control the flow. If it's just some water collecting there and draining, it's not really a problem as long as the seals around the glass look like they have integrity and aren't gapped or torn. If the water drains in your experiment, then any water seeping around the seals will drain without damaging your trim. Often small leaves will block those drain holes and tubes.