Summary
Shell namespace extensions generate a SHCNE_CREATE notification when a new item is added to a folder. The new item is added to the view window of any open browser windows displaying the contents of the parent folder of the new item when the SHCNE_CREATE notification is processed. However, in namespace extensions that uses the default shell view implementation (DefView) the new item is appended at the end of the list of items already displayed in the view window instead of being sorted based on the current sort criteria.
More Information
In addition to generating a SHCNE_CREATE notification, a namespace extension can also generate a SHCNE_UPDATEDIR notification to notify the view window that the contents of the shell folder have changed. Although the contents of the view are sorted, generating a SHCNE_UPDATEDIR notification can be an expensive operation for some shell namespace extensions as DefView re-enumerates the contents of the shell folder when handling a SHCNE_UPDATEDIR notification.