If you ever have a compiler warning saying

A custom tool ‘PublicResXFileCodeGenerator’ is associated with file ‘blah’, but the output of the custom tool was not found in the project. You may try re-running the custom tool by right-clicking on the file in the Solution Explorer and choosing Run Custom Tool.

To remove the compiler warning you can just remove the Custom Tool by clicking on the Resource file, pressing F4 to bring up the Properties and then removing the entry for Custom Tool. Easy.