The FMEVENT_HELPSTRING message is sent to a File Manager extension DLL procedure when File Manager wants a help string for a menu or toolbar command item.
FMEVENT_HELPSTRING lpfmshs = (LPFMS_HELPSTRING) lParam; /* pointer to data transfer structure */
The FMS_HELPSTRING structure identifies the command item for which a help string is wanted, along with a handle to its menu. An application then writes the appropriate help string to the FMS_HELPSTRING structure’s szHelp member.
An extension DLL procedure should return zero if it processes this message.