You can also provide contextual Help for a property sheet, dialog box, or message box by including a Help button in that window, as shown in
Figure 12.8. When the user chooses the Help command button, display the Help information in a Help secondary window, rather than a context-sensitive Help pop-up window.
Figure 12.8 A Help button in a secondary window
The user assistance provided by a Help command button differs from the "What's This?" form of Help. Command button Help should provide an overview, summary assistance, or explanatory information for that window. For example, for a message box, it can provide more information about causes and remedies for the reason the message was displayed. Consider the Help command an optional, secondary form of contextual user assistance, not a substitute for context-sensitive, "What's This?" Help. Don't use it as a substitute for clear, understandable designs for your secondary windows.