Using Advanced Resource File Techniques
You can use the Resource Includes command on the View menu to modify the environment’s normal working arrangement of storing all resources in the project .rc file and all symbols in Resource.h. For more information on symbols, see Symbol Editor Topics.
In the Resource Includes dialog box, use the Symbol header file box to change the name of the header file where the symbol definitions for your resource file are stored.
Use the Read-only symbol directives box to include header files that contain symbols that should not be modified during an editing session. For example, you can use the Read-only symbol directives box to include a symbol file that has been created to be shared among several projects. You can also use this box to include MFC .h files.
Use the Compile-time directives box to include resource files that:
Are created and edited separately from the resources in your main resource file.
Contain compile-time directives, such as directives that conditionally include resources.
Contain resources in a custom format.
The Compile-time directives box is also used to include standard MFC resource files.
Once you’ve made changes to your resource file using the Resource Includes dialog box, you need to close the file and then reopen it for the changes to take effect.