[platform-dev] IDocumentSetupParticipant --> teardown?

[Christoph Läubrich <laeubi@xxxxxxxxxxxxxx>]

IDocumentSetupParticipant allows me to participate in the setup of a 
document e.g. I can register a document listener.

But how do I know the document is supposed to vanish? (e.g. editor 
closed, document replaced...) I think I can try to register some 
listners for textbuffers/viewers but it seems a bit strange to use 
IDocumentSetupParticipant to decouple from the details just to then gets 
back to those...