No, I know what it is, the same thing happened on my 86 560 SEC. Towards the base of the arm the top should pop off just like many modern day cars but mine for some reason won't. The SE model does not do this????
1986 560 SEC *Sold* < Big Mistake I miss my baby!
1988 300SE *Sold*
1989 300CE - current car, but not for too long