Hi there,
I've created a content type based on Document Set (everything without VisualStudio). I created an item, clicked it and it showed the docsethomepage.aspx as it should. The ribbon gave me the Page/Edit option, so I could add a Filter WebPart, and as I was on an actual item, I could chose from current columns. I saved it and all was fine, the customized docsethomepage worked on every other document set.
A couple of features later (actually only the PublishingInfrastructure, I think) when I clicked a docset (same doclib, maybe added a column), the ribbon on the docsethomepage suddenly didn't give me the "edit page" option anymore but it displayed as normal library. From that moment on I was only able to edit the docsethomepage by navigating to the content type and to the advanced settings. That was giving me 2 problems:
1. The current item context was lost, and adding a filter webpart didn't give me the option to chose from the document set's columns.
2. When I edited the docsethomepage by adding a list view, clicking a document set in the library didn't bring me to the docsethomepage anymore but straight to the list. This was happening only with some items though, others were showing the normal docsethomepage (same library, same content type).
Has anyone an explanation for this?