Canvas corners

[nconniej52]

Has anyone had trouble with the plastic part shrinking? Seems like with the weather the corners on the bed end on the outside won't go together and when it rains it leaks in there. Any solutions

 

[Steve88W]

The zipper on two of my windows have ripped away from the plastic due to aging/shrinkage.
The 'rip' is only a few inches long but I can't completely close those two windows now.

I'm looking around for an upholstery shop to see what they can do to fix it.
I suspect that this is a pretty common problem.