USe the window weld from 3M it works great. But to insure that it does not happen agian there are a few easy things to do. Here is what I wrote on another site about what I found in my drivers door:
Checked the glass last night and the glass has come out of the rear bracket. I also did find the up adjustment but it is not on the motor as you said it is part of the problem that these mustang have with the glass coming out of the rear bracket. The stop on the rear of the glass used the back of the rear bracket as the point of contact to stop the window. This causes a moment on the bracket that probably contributes the glass coming un-glued. Once it has come unglued the stop bracket then causes the bracket to rotate down which in turn pushed the rear of the window up causing it to sit to high and in my case rub the roof trim
You will probably notice that the rivet that holds the window channel to the regulator has become loose, if you just re-glue the glass it will come back out b/c of what I said above.
I fixed it by replaceing the rivet that holds the window channel on the regulator with a 1/4" SS bolt, lock washer and nut. I also added a #10 SS nut, bolt and washer next to the river to prevent the moment being put on the window channel when it reaches the up stop.
I have some drawings of what I did but I will have to find them.....