Called by the framework to write the size and location of the main frame window to the registry.
virtual BOOL StoreWindowPlacement( const CRect& rectNormalPosition, int nFlags, int nShowCmd );
By default, MFC automatically saves the position and state of the main frame window before the application exits. This information is stored in the Windows registry under the WindowPlacement key in the default registry location for your application. For more information about the default registry location of your application, see CWinAppEx::GetRegistryBase.
Override this method if you want to store additional information about the main frame window.