Called by the framework when the user presses the F1 key.
afx_msg BOOL OnHelpInfo( HELPINFO* lpHelpInfo );
Pointer to a HELPINFO structure that contains information about the menu item, control, dialog box, or window for which help is requested.
Returns TRUE if a window has the keyboard focus or if a menu is active within a window. If no window has the keyboard focus, returns FALSE.
If a menu is active when F1 is pressed, WM_HELP is sent to the window associated with the menu; otherwise, WM_HELP is sent to the window that has the keyboard focus. If no window has the keyboard focus, WM_HELP is sent to the currently active window.