diff -up lablgtk-2.16.0/src/gtkThread.ml.orig lablgtk-2.16.0/src/gtkThread.ml
--- lablgtk-2.16.0/src/gtkThread.ml.orig	2012-08-23 04:37:48.000000000 -0600
+++ lablgtk-2.16.0/src/gtkThread.ml	2012-10-17 10:49:34.581065898 -0600
@@ -28,8 +28,14 @@ open GtkMain
 
 let jobs : (unit -> unit) Queue.t = Queue.create ()
 let m = Mutex.create ()
+type ('a, 'b) either = Left of 'a | Right of 'b
 let with_jobs f =
-  Mutex.lock m; let y = f jobs in Mutex.unlock m; y
+  Mutex.lock m;
+  let y = try Left (f jobs) with exn -> Right exn in
+  Mutex.unlock m;
+  match y with
+  | Left y -> y
+  | Right exn -> raise exn
 
 let loop_id = ref None
 let reset () = loop_id := None
@@ -40,8 +46,6 @@ let cannot_sync () =
 let gui_safe () =
   not (Sys.os_type = "Win32") || !loop_id = Some(Thread.id (Thread.self ()))
 
-let has_jobs () = not (with_jobs Queue.is_empty)
-let n_jobs () = with_jobs Queue.length
 let do_next_job () = with_jobs Queue.take ()
 let has_timeout = ref false
 let async j x = with_jobs
@@ -71,10 +75,10 @@ let sync f x =
 let do_jobs_delay = ref 0.013;;
 let set_do_jobs_delay d = do_jobs_delay := max 0. d;;
 let do_jobs () =
-  for i = 1 to n_jobs () do do_next_job () done;
+  let rec loop () = do_next_job (); loop () in
+  (try loop () with Queue.Empty -> ());
   true
 
-
 (* We check first whether there are some event pending, and run
    some iterations. We then need to delay, thus focing a thread switch. *)