Eclipse > VSC: Symbol Not Found

Hi,

As per a previous thread, I am moving all my 50 projects from Eclipse to VSC.  

I am getting a runtime error, which I wasn't getting previously

Error: Symbol Not Found Error 
Details: Could not find symbol 'DeviceName'

The resource file is, which is in a sub-folder.

<resources>
    <string id="AppName">hTemp</string>
    <string id="DeviceName">Vivoactive</string>
</resources>

It compiles and picks up the AppName ok.

Any ideas?

Thanks

Chris