diff --git a/library/bootstrap/boot-stage3.factor b/library/bootstrap/boot-stage3.factor
index 4097bd1dd3..f4450b7d9a 100644
--- a/library/bootstrap/boot-stage3.factor
+++ b/library/bootstrap/boot-stage3.factor
@@ -120,8 +120,8 @@ t [
     "/library/ui/editors.factor"
     "/library/ui/menus.factor"
     "/library/ui/presentations.factor"
-    "/library/ui/tiles.factor"
     "/library/ui/panes.factor"
+    "/library/ui/tiles.factor"
     "/library/ui/dialogs.factor"
     "/library/ui/inspector.factor"
     "/library/ui/init-world.factor"
diff --git a/library/in-thread.factor b/library/in-thread.factor
deleted file mode 100644
index 392e7404bb..0000000000
--- a/library/in-thread.factor
+++ /dev/null
@@ -1,18 +0,0 @@
-! Copyright (C) 2004, 2005 Slava Pestov.
-! See http://factor.sf.net/license.txt for BSD license.
-IN: threads USING: errors io-internals kernel lists ;
-
-: in-thread ( quot -- )
-    #! Execute a quotation in a co-operative thread. The
-    #! quotation begins executing immediately, and execution
-    #! after the 'in-thread' call in the original thread
-    #! resumes when the quotation yields, either due to blocking
-    #! I/O or an explicit call to 'yield'.
-    [
-        schedule-thread
-        ! Clear stacks since we never go up from this point
-        [ ] set-catchstack
-        { } set-callstack
-        try
-        stop
-    ] callcc0 drop ;
diff --git a/library/threads.factor b/library/threads.factor
index 86fb457043..bcddc33257 100644
--- a/library/threads.factor
+++ b/library/threads.factor
@@ -2,8 +2,7 @@
 ! Copyright (C) 2005 Mackenzie Straight.
 ! See http://factor.sf.net/license.txt for BSD license.
 IN: threads
-USING: errors io-internals kernel kernel-internals lists
-namespaces ;
+USING: errors kernel kernel-internals lists namespaces ;
  
 ! Core of the multitasker. Used by io-internals.factor and
 ! in-thread.factor.
diff --git a/library/ui/world.factor b/library/ui/world.factor
index 648e3f2ec3..2923a76a1f 100644
--- a/library/ui/world.factor
+++ b/library/ui/world.factor
@@ -1,8 +1,9 @@
 ! Copyright (C) 2005 Slava Pestov.
 ! See http://factor.sf.net/license.txt for BSD license.
 IN: gadgets
-USING: alien errors generic kernel lists math memory namespaces
-prettyprint sdl sequences stdio strings threads ;
+USING: alien errors generic kernel lists math
+memory namespaces prettyprint sdl sequences stdio strings
+threads ;
 
 ! The world gadget is the top level gadget that all (visible)
 ! gadgets are contained in. The current world is stored in the
@@ -43,10 +44,12 @@ DEFER: handle-event
         drop f
     ] ifte ;
 
+: next-event ( -- event ) <event> dup SDL_PollEvent ;
+
 : run-world ( -- )
     #! Keep polling for events until there are no more events in
     #! the queue; then block for the next event.
-    <event> dup SDL_PollEvent [
+    next-event [
         [ handle-event ] in-thread drop run-world
     ] [
         drop world get world-step [ yield run-world ] when
diff --git a/library/unix/io.factor b/library/unix/io.factor
index dc0677ea2a..4296203cce 100644
--- a/library/unix/io.factor
+++ b/library/unix/io.factor
@@ -355,6 +355,9 @@ M: writer stream-close ( stream -- )
 : <fd-stream> ( infd outfd flush? -- stream )
     >r >r <reader> r> <writer> r> <duplex-stream> ;
 
+: idle-io-task ( -- )
+    [ schedule-thread 10 io-multiplex ] callcc0 idle-io-task ;
+
 USE: stdio
 
 : init-io ( -- )
@@ -363,12 +366,5 @@ USE: stdio
     global [
         <namespace> io-tasks set
         0 1 t <fd-stream> stdio set
-    ] bind ;
-
-IN: threads
-
-: stop ( -- )
-    #! If there is a quotation in the run queue, call it,
-    #! otherwise wait for I/O.
-    pending-io? [ 10 io-multiplex ] when
-    next-thread [ call ] [ -1 io-multiplex stop ] ifte* ;
+    ] bind
+    [ idle-io-task ] in-thread ;