WebStorm 4.0 EAP 114.282 doesn't recognize javascript classes

When I use Navigate | Class... or press Ctrl+N and search for any javascript class name in my project I always get 'No matches found'. Is this feature for PHP code only? If not then how should I define my classes for WebStorm to recognize them?

Currently all my classes are defined in this form:

(function(){
...
namespace.ClassName = function ClassName(){ /* code */ };
...
}());

I tried the following with the same results:

(function(){
...
function ClassName(){ /* code */ }
namespace.ClassName = ClassName;
...
}());