The framework calls this member function as a user rotates the mouse wheel and encounters the wheel's next notch.
Unless overridden, OnRegisteredMouseWheel routes the message to the appropriate window (the parent window with focus), and calls the WM_MOUSEWHEEL handler for that window.
Override this member function to provide your own message routing or to alter the mouse-wheel scrolling behavior.
OnRegisteredMouseWheel handles messages for Windows 95/98 and Windows NT 3.51. For Windows NT 4.0 message handling, use OnMouseWheel.