>I would like to use the What's This Help on a form. After specifing all of the WhatsThis properties, the "?" appears on the title bar in design mode but does not appear when the form is run.
>
>What do you have to do to get the "?" to appear on the form?

Setup the following properties of your form:

WhatsThisButton = .T.
WhatsThisHelp = .T.
WhatsThisHelpID = nContextID 
* It depends on your help file. 
* In general you should set it to 0 (zero) for the form, so that it searches for ContextIDs of the controls. 
* See FoxPro Help for WhatsThisHelpID property
MaxButton = .F.
MinButton = .F.
* You can have one of the max or min buttons but not both of them together with WhatsThis. This is by design.

Check out also http://www.kbalertz.com/kb_247241.aspx

HTH