I have a small tear/crack in one of my clear vinyl windows. It is basically where the window was creased when the camper was closed up. I have the clear windows zipped up when I close up the camper. Is this the proper way to do it? When I open it up there are several creases in the clear vinyl and I'm worried it will all lead to cracking. Anybody else experienced this? Any ideas for an effective patch? Thanks for your time!