diff -r 3a3d9de2ad6e -r bb3469024b6a src/Pure/Concurrent/simple_thread.scala
--- a/src/Pure/Concurrent/simple_thread.scala	Mon Sep 20 19:00:47 2010 +0200
+++ b/src/Pure/Concurrent/simple_thread.scala	Mon Sep 20 21:20:06 2010 +0200
@@ -27,11 +27,11 @@
 
   /* thread as actor */
 
-  def actor(name: String, daemon: Boolean = false)(body: => Unit): Actor =
+  def actor(name: String, daemon: Boolean = false)(body: => Unit): (Thread, Actor) =
   {
     val actor = Future.promise[Actor]
     val thread = fork(name, daemon) { actor.fulfill(Actor.self); body }
-    actor.join
+    (thread, actor.join)
   }
 }