Unfortunately Tesla supplies a trunk shelf without lift function with its Model S. This means that when opening the trunk, the shelf has to be folded up by hand each time and then folded down again by hand before closing it, otherwise the view through the rear window is impaired. Fortunately, there are enough third party manufacturers that offer different constructions to install an automatic lift in the form of a thread or string.
Personally, I like Norm’s version, the “Shelf Butler,” best. But unfortunately for European Drivers, it can only be ordered directly in the USA. Here is a video about it.
(Contact details of Norm for an order are in the description of the video)
This versions of a lift are also available in Europe: