When a class defines new items for its pop-up menu, it also must provide for the processing of the help for these items when the user requests it. This is accomplished by overriding wpMenuItemHelpSelected inherited from WPObject. Given the item selected by the user, the method override for wpMenuItemHelpSelected calls wpDisplayHelp inherited from WPObject to display the Help dialog window for that item. The wpDisplayHelp method requires the ID for the help panel associated with the item, as well as the name of the help library where it resides.

The implementation of the CAR object also demonstrates the use of:

• A release order list in CAR.IDL.

• External stem and prefix attributes in the class section of CAR.IDL. This allows the debugging process to be easier, because method names are externalized.

• A message queue for the Workplace Shell. Object code runs on the Workplace Shell's thread. Windows associated with objects receive messages through the Workplace Shell's message queue. Objects do not need their own message queues.