title: Firefox isn't showing typescript (.ts) source maps in the debugger
body: <p>I can only see the .js files, the .ts sources don't appear in Firefox.</p>
  
  <p>It works in Chrome, I can see and place line breaks in .ts files, and the debugger works great. But Firefox will not work, no version, not the stable or the nightly or the developer version.</p>
  
  <p>Could it be that the functionality is not implemented on Mac/OSX? If so, there should be something on the internet about that, but I've found nothing. Apparently, the problem has not been documented anywhere.</p>
  
  <p>Does anyone have any knowledge of this, and perhaps how to fix it?</p>