What adhesive should I use for a door seal?

The rubber door seal on the passenger door of my 2018 Seat Ateca is coming away from the door. Do you have any idea what fixative is used and if not can you recommend a suitable glue to carry out the repair?

What's the best adhesive to fit a rubber seal on a gearbox cover?

I have Triumph Vitesse Convertible 2L Mk2. I have had to remove the rubber seal on the gearbox cover due to old age and have obtained the new rubber seal but it needs to be glued to the cover. It is the...