is glue the only option? if so what sort??

 

Pull it off and use 3M spray on adhesive......

 

how did it happen. i would use like a blunt ( not sharp) flat object and try to shove it back in..if that works.

 

Kevin, This often happens with my car and I did try glue and many other stuff nothing is a permanent solution except you have to take that part out and get it refitted fabric from car interior professionals. Be careful with glue creates more mess then you think even if your are using transparent.

akabond, It happens with me most of the time due to heat, because in my area normally we often see 60+ C

 

Heat, moisture, design, etc. It is like a bad head liner. Replace it or have it recovered.