Some sliding patio door systems have experienced the problem of rain water seeping behind the exterior cladding at the bottom of the glass.  To prevent such problems, we recommend running a bead of clear silicone caulk along the horizontal seam where the bottom of the glass meets the cladding. If the water has saturated the wood beneath for some time, the wood will swell and the cladding will bulge out.  This can cause the operating door to scrape the cladding at this point. To remedy this situation, it is recommended that the