What is swDocumentTypes_e.swDocSDM and where should I be using it?

My C# addin's menu position was being set with cmdGroup.set_MenuPosition( swDocumentTypes_e.swDocASSEMBLY ) but it was not correct for assembly docs until I used cmdGroup.set_MenuPosition( swDocumentTypes_e.swDocSDM ).

What is swDocumentTypes_e.swDocSDM for and are there other plaves I should be using it instead of swDocumentTypes_e.swDocASSEMBLY?

Thanks!

SolidworksApi macros