Executing the ControlHelp method and as a parameter passing another control on the form causes the passed control to execute the Popup Help (assuming some Popup Help text has been specified for it).
Example
The following code is all that is required to initiate Popup Help for a specific control. It assumes the TMFMHelp control is named MFMHelp1. The call to the ControlHelp method is inside a response method for an event caused by a click on a Popup Menu with the text " What's This? ". Note the parameter being passed is the Popup Menu's PopupComponent property, which contains a reference to the Component that last "popped up" the Popup Menu. In this way you can assign the same popup menu with a " What's This? " item to all controls and use a single method to implement the Popup Help. For more information see the source for the demo.
procedure TForm1.WhatsThis1Click(Sender: TObject);
begin
MFMHelp1.ControlHelp(PopupMenu1.PopupComponent);
end;