Its glued on. you need to strip the door, get the glass out and reglue it. Be very careful removing the door trim, very easy to bend the top corner near the top rear of the door
The rubber section is glued to the black trim piece This was a problem on the European 101 cars when they came over into Germany. Our solution was to make up a thin hardboard former which held the rubber in the correct position which slid in between the glass and the seal. We then put more adhesive in between the seal and the black trim and left it to set with the former in position for 24 hours. It held up well.
Dave
www.gt101.co.uk
Ed, Are you certain the trim hasn't warped (comparing driver and passenger side)? San Joaquin Valley summers will warp most anything, including minds.
If the rubber is still glued to the trim, I would suspect the trim.
In your first pic the window seal is definitely coming away from the metal frame. With the window completely down you may be able to reglue it,, Here are some pics off a spare door