You have a broken lifting angle, and the other one will break soon if you don't replace it, or the actuating bridge will get sidways and jam (open, of course....!).
Repair is pretty easy so long as the roof still opens.
Open roof, remove liner by unclipping the four clips about 2" back from the front edge and sliding out from above. It doesn't fit out the bottom unless you bend it.
Remove the two chome rails (crosshead screws -- leave the slotted screws alone, they adjust the height). close roof, undo the two screws on the angle brackets on each side, and remove the roof panel. Unscrew the three screws on each side of the bridge that hold lifting angles to the bridge. Lift the angle brackets and unhook the rain gutter (fits into the back of the roof panel and under the rear of the opening) -- take care not to force it or you will break it.
The lifting angles (or the remains thereof) hook under the side rails. Remove, clean out all the junk, then replace with new ones ($90 each, alas, but worth it, they are MUCH better than the originals!).
Lubricate the sliding pads with MB sliding sunroof paste -- you will need to beg this, it only comes in a 500g can -- get your indy to sell you enough to do the job. Nothing else works properly, WD-40 especially.
Installation is the reverse of removal. You will need to have the lifting angles all the way forward, but not tilted up, to re-install the roof panel. Shove it all the way forward into the seal when you put it back on, or it won't open or close properly (it will run up on the rear seal).
Don't shove down on it to close it, you will either break the other lifting angle or jam the bridge at a funny angle, in which case you cannot remove the liner from the top, and will likely damage it taking it out from the inside.
Messy job, but not hard.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!