.....and I couldn't fix it. I found a cheap magnetic-close screen 'door' at a dollar store. (It was $3) And decided to try to replace the opening. So we set up the PUP (we're having beautiful weather down here in West Central Alabama) pulled out the awning, and set up the screen, and I started pinning. Then we took screen room down, and I sewed. On a standard sewing machine. Very hard to maneuver all that screen fabric from a 14' screen enclosure. Whew. When I was done sewing, I cut out the old part of screen with zipper, and we put the screen room back up again.
It wouldn't close. The magnets on the cheap screen 'door' were too weak. And I had cut away a little too much of the original screening. (Probably shouldn't have pinned the zipper closed)
Oh my. What to do. Slept on it all night, and came up with a plan. Went to Home Depot next day and bought 2 sets of their strongest pairs of magnet strips. (2.50 each) Placed them in little pouches and sewed them to the magnetic strip trim on door.
Well-VOILA-opens and closes like a dream. So much better than the zipper, because now when my hands are full, I can just walk right through the door and it latches closed behind me.
So, on hindsight, I would definitely do this replacement again. But I would buy the better magnetic latch door from Home Depot (about $20) and I would leave more of the original screen so it doesn't close so tight.