For the past few days, the headlining of my 1997 E200 W210 is suddenly drooping down across the full width of the front of the car, above the driver and passenger seats. It seems to be sagging by nearly 2 inches and is continually dragging in my hair as I am driving. If I push it up and smooth it along the underside of the car roof, it stays put for a few minutes, but gradually droops down again. Other than not sticking where it should, the material looks in good condition and is not marked or damaged.

Does anyone know of any quick fixes to stick this headlining back up, or is it likely to mean an expensive shop repair job? Any help would be appreciated. By the way, I am in Singapore, in case that makes a difference.