Driver window keep jumping off the holding screw!!

[Tymatk]

Hi

My driver side window keep jumping off the screw that is designed for it to remain in place and sit on the arm that moves up and down.

What happens was once in a while when i wind the windown down all the way, the glass jumps off the rail and sit on the bottom of the door and i just couldn't wind it back up again.

At first, i thought it was the window regulator but when i tried operating the window switch to bring it up, i could feel that the motor is working but something is stopping it from lifting the window up. After removing all the door trim and stuffs to get to the glass, it took me a while to realised that the glass has jumped off this little screw for it to sits on.

I lift it up and push it back in but i could see that it'll definately falls off again so i gave it some silicon to hold it in place but this didn't last long as sillicon was not strong enough, the bastard fell out again so this time i used Wurth KD bond which is a type of flexible glue.

It's been good so far but what i'd like to know is was there something like a rubber O-ring, some special material type washer that BMW used to stop the glass from falling off as i could see there was NO thread to put a nut on this screw.

Thank you

PS. If it falls off again, i'll take some good pic to show.