Extender Control Just Won't Pick Up Localization

Imagine my surprise when, having gone through the AJAX localization tutorial and this MSDN article up, down and sideways, I couldn’t get my extender control to see resource strings on the client!

Here’s the extender skeleton:

[assembly: WebResource (
    "[blah].js",
    "text/javascript")]

[assembly: ScriptResource (
    "[blah].js", 
    "[blah recources]", 
    "ClientResources"]

namespace MyControls
{
 public class MyExtender : ExtenderControl
 {
  // Lots of stuff skipped
  protected 
      override IEnumerable<ScriptReference> GetScriptReferences()
  {
   yield return new ScriptReference (
       Page.ClientScript.GetWebResourceUrl (
                 typeof (MyExtender), "[blah].js")
    );
  }
 }
}

I don’t remember why I chose GetWebResourceUrl, but that’s precisely where the problem lies. Change the line to this and everything magically works:

yield return new ScriptReference ("[blah].js",
                        this.GetType ().Assembly.FullName);

Gotta love obscure edge-cases.