I had what sounds like the same issue with my shower door. The front edge of the door sagged on the lower corner of the door. The vinyl door sweep would catch on the shower's "sill" and make it hard to open or close. For my shower unit, according to Jayco and the dealer, there was no way to adjust the door. Instead, the dealer had to insert a shim, an extra piece of aluminum, along one edge of the shower enclosure (next to where the shower unit abutted a wall) to true up the swing of the door. This was about a year ago, and so far the door has stayed properly adjusted.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch