From a past work experience it appears that the plasticizer used in these window surrounds was not of the highest quality. The high heat locations around the world actually cause the plasticizer to slowly evaporate or ooze out of the vinyl leaving a more brittle and shrunken material. This is especially true when the cars are closed up and out in the sun.

Mine have all lost enough that they are now about an inch above the point where they should meet the door panel material. However I have not removed any of them yet. On a parts car, the pieces had actually broken and split so I attempted to remove what was left of one. It was by then not too difficult, and the painted door frame did not look too strange. Not really sure if there was any adhesive used at all or if they were simply a press-fit under the weather stripping?!?

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150