Assembly: Microsoft.VisualStudio.Shell.Interop (in Microsoft.VisualStudio.Shell.Interop.dll)
VSPackages call OnSelectChange when the current selection has changed and the Properties window must be updated to display its properties. With the call VSPackages pass in their ISelectionContainer interface pointer. ISelectionContainer provides access to one or more IDispatch objects that the environment uses to update the Properties window.
The ISelectionContainer pointer is one part of the selection context that the environment maintains for every window. The selection context also includes an IVsHierarchy pointer for access to the current hierarchy, an item identifier (VSITEMID) indicating the current item, and an array of element values. VSPackages use the SVsTrackSelectionEx service to report changes to these other selection context items.
The SID for this service is SID_STrackSelection.
Editors and designers that only need to change the ISelectionContainer for the property browser should use STrackSelection. Windows, like the Solution Explorer, that change the active Hierarchy/itemid need to use SVsTrackSelectionEx.