Sometime it’s necessary to put resource files (globalization and localization) in another project for modularization purpose.
However, in order for the resources files to be available for other project, the access modifier must be made public.
If you found the “Access Modifier” is grey-ed out, change the “Custom Tool” property in the file’s properties to “PublicResXFileCodeGenerator”
Another case is to have this build as “Embedded Resource”. This is not necessary unless you output the library files and drop them to another solution.