The active desktop is set by the system every time the Workplace Shell is initialized, or any time the user profile is reset by a call to PrfReset. Because there can be only one active desktop and objects cannot change their class, desktop objects and descendants must call wpIsCurrentDesktop to determine if it is the current desktop. Desktop folders which are not active take on the behavior of standard folder objects.
For more information about PrfReset, see the Presentation Manager Programming Reference.