Geoff Chappell - Software Analyst
The IObjectWithQuerySource methods are (as ordered in the virtual function table after the IUnknown methods):
HRESULT SetSource (IQuerySource *);
HRESULT GetSource (REFIID, PVOID *);
in which IQuerySource is an undocumented interface.
The IObjectWithQuerySource interface is implemented by SHELL32.DLL version 6.00 and higher.
Though this interface dates from 2001, it was still not documented by Microsoft as late as the January 2007 edition of the Windows Vista Software Development Kit (SDK).