Windows provides functions you can use to change existing menus and create new menus while your application runs. This section explains:
How to enable and disable menu items
How to check and uncheck menu items
How to add, change, and delete menu items
How to use bitmaps as menu items
How to replace a menu
How to create and initialize a menu from your application
When a window is created, it receives a private copy of the class menu. The application can alter that window's copy of the menu without affecting other windows' menus.
NOTE:
Whenever you make changes to items on the menu bar, you need to call the DrawMenuBar function to display the changes.