Call this member function to activate and restore the frame window so that it is visible and available to the user.
This member function is usually called after a non-user interface event such as a DDE, OLE, or other event that may show the frame window or its contents to the user.
The default implementation activates the frame and brings it to the top of the Z-order and, if necessary, carries out the same steps for the application's main frame window.
Override this member function to change how a frame is activated. For example, you can force MDI child windows to be maximized. Add the appropriate functionality, then call the base class version with an explicit nCmdShow.