I was driving down the highway with the windows down and the sunroof open. I looked in my rearview mirror and noticed the rear part of the headliner flapping up and down, hitting the rear headrests. Upon closer inspection (after stopping) I noticed that there is nothing really holding the headliner in place, just the curve of the material. This is hardly enough to support the strength of the wind at higher speeds. Has anyone experienced this and possibly came up with a fix? Any help would be greatly appreciated.