Referencing TypeScript file includes whole file in output

I have created a new Windows 8 JavaScript Blank app with TypeScript 0.8.1 and Web Essentials installed.

I have added both a file foo.ts and bar.ts to my project.

foo.ts contains only a simple class:

class Foo
{ }

bar.ts contains a reference to foo.ts and a class bar:

/// <reference path="foo.ts" />

class Bar
{ }

The strange thing is that bar.js contains both the Bar and Foo class:

var Foo = (function () {
    function Foo() { }
    return Foo;
})();
var Bar = (function () {
    function Bar() { }
    return Bar;
})();

What is going wrong? I'm working on a larger project with a shared reference.ts file. Suddenly all my ts files are compiled to each javascript file.