Auto-complete for modules not working?

Question

JavaScript

Good afternoon.
There is phpstorm 9.
There is a main.js file
someModule.f();
There is a script.js file

var someModule = (function(){
    window._w = {
      f: function(){
         return 1;
     }
    };
    return {
      f: function(){
         return 1;
     }
}
}());

If the current script file is in the editor, then auto-complete works for someModule.
If a file is opened, for example main, then auto-complete for someModule no longer works.
But auto-complete in the main file works for the _w I specified in window.
Is this a bug or a feature?
UPD:
the files are included in the general html (did not write right away)