diff --git a/collects/setup/xref.ss b/collects/setup/xref.ss
index 2b44426bb4..1b127664a2 100644
--- a/collects/setup/xref.ss
+++ b/collects/setup/xref.ss
@@ -12,22 +12,22 @@
 (define (get-dests dir)
   (let* ([i (get-info/full dir)]
          [scribblings (i 'scribblings)])
-  (map (lambda (d)
-         (and (not (and (list? d)
-                        ((length d) . > . 2)
-                        (pair? (list-ref d 2))
-                        (eq? (car (list-ref d 2)) 'omit)))
-              (pair? d)
-              (let* ([flags (if (pair? (cdr d)) (cadr d) null)]
-                     [name (if (and (pair? (cdr d)) (pair? (cddr d)) 
-                                    (pair? (cdddr d)))
-                               (cadddr d)
-                               (let-values ([(base name dir?) (split-path (car d))])
-                                 (path-replace-suffix name #"")))])
-                (build-path
-                 (doc-path dir name flags)
-                 "out.sxref"))))
-       scribblings)))
+    (map (lambda (d)
+           (and (not (and (list? d)
+                          ((length d) . > . 2)
+                          (pair? (list-ref d 2))
+                          (eq? (car (list-ref d 2)) 'omit)))
+                (pair? d)
+                (let* ([flags (if (pair? (cdr d)) (cadr d) null)]
+                       [name (if (and (pair? (cdr d)) (pair? (cddr d)) 
+                                      (pair? (cdddr d)))
+                                 (cadddr d)
+                                 (let-values ([(base name dir?) (split-path (car d))])
+                                   (path-replace-suffix name #"")))])
+                  (build-path
+                   (doc-path dir name flags)
+                   "out.sxref"))))
+         scribblings)))
 
 (define (load-collections-xref [report-loading void])
   (or cached-xref
diff --git a/collects/tests/mzscheme/prompt-tests.ss b/collects/tests/mzscheme/prompt-tests.ss
index a6579834ee..60c9bcf5f3 100644
--- a/collects/tests/mzscheme/prompt-tests.ss
+++ b/collects/tests/mzscheme/prompt-tests.ss
@@ -1693,7 +1693,52 @@
       (test s sync s)))
   (go (lambda (f) (f)))
   (go (lambda (f) (dynamic-wind void f void))))
-  
+
+;; ----------------------------------------
+;; Second continuation spans two meta-continuations,
+;;  and cuts the deeper meta-continuation in half:
+
+(test
+ '("x1")
+ 'nested-half
+ (let* ([says null]
+        [say (lambda (s)
+               (set! says (cons s says)))]
+        [a (make-continuation-prompt-tag 'a)]
+        [b (make-continuation-prompt-tag 'b)])
+   (let ([ak
+          (with-continuation-mark 'x "x0"
+            (call-with-continuation-prompt
+             (lambda ()
+               (with-continuation-mark 'y "y0"
+                 (let ([bk (call-with-continuation-prompt
+                            (lambda ()
+                              (let ([f (call-with-composable-continuation
+                                        (lambda (k)
+                                          (lambda () k))
+                                        b)])
+                                (say "bcall")
+                                (begin0
+                                 (f)
+                                 (say "breturn"))))
+                            b)])
+                   (call-with-continuation-prompt
+                    (lambda ()
+                      ((bk (lambda ()
+                             (let ([f (call/cc (lambda (k) (lambda () (lambda () k))) a)])
+                               (begin0
+                                (f)
+                                (say "areturn")))))))
+                    b))))
+             a))])
+     (with-continuation-mark 'x "x1"
+       (call-with-continuation-prompt
+        (lambda ()
+          (ak (lambda () 
+                (lambda ()
+                  (continuation-mark-set->list (current-continuation-marks) 'x)))))
+        a)))))
+
 ;; ----------------------------------------
 ;; Try long chain of composable continuations
 
diff --git a/src/mzscheme/include/scheme.h b/src/mzscheme/include/scheme.h
index 1de3b1dc32..a073f5b95a 100644
--- a/src/mzscheme/include/scheme.h
+++ b/src/mzscheme/include/scheme.h
@@ -924,6 +924,7 @@ typedef struct Scheme_Thread {
 
   mz_jmp_buf *error_buf;
   Scheme_Continuation_Jump_State cjs;
+  struct Scheme_Cont *decompose;
 
   Scheme_Thread_Cell_Table *cell_values;
   Scheme_Config *init_config;
diff --git a/src/mzscheme/src/eval.c b/src/mzscheme/src/eval.c
index 8c19f1e6a0..918da6fab9 100644
--- a/src/mzscheme/src/eval.c
+++ b/src/mzscheme/src/eval.c
@@ -7093,6 +7093,8 @@ Scheme_Object *scheme_jump_to_continuation(Scheme_Object *obj, int num_rands, Sc
         scheme_longjmpup(&overflow->jmp->cont);
       }
     } else {
+      /* The prompt is different than when we captured the continuation,
+         so we need to compose the continuation with the current prompt. */
       p->cjs.jumping_to_continuation = (Scheme_Object *)prompt;
       p->cjs.num_vals = 1;
       p->cjs.val = (Scheme_Object *)c;
@@ -7121,12 +7123,18 @@ Scheme_Object *scheme_jump_to_continuation(Scheme_Object *obj, int num_rands, Sc
         }
         p->meta_continuation = prompt_mc->next;
         p->stack_start = prompt_mc->overflow->stack_start;
+        p->decompose = prompt_mc->cont;
         scheme_longjmpup(&prompt_mc->overflow->jmp->cont);
       } else if ((!prompt->boundary_overflow_id && !p->overflow)
                  || (prompt->boundary_overflow_id
                      && (prompt->boundary_overflow_id == p->overflow->id))) {
         /* Jump directly to the prompt: destination is in
            scheme_finish_apply_for_prompt() in fun.c. */
+        if (!p->meta_continuation)
+          scheme_signal_error("internal error: no meta-cont for escape");
+        if (p->meta_continuation->pseudo)
+          scheme_signal_error("internal error: trying to jump to a prompt in a meta-cont"
+                              " that starts with a pseudo prompt");
         scheme_drop_prompt_meta_continuations(c->prompt_tag);
         scheme_longjmp(*prompt->prompt_buf, 1);
       } else {
diff --git a/src/mzscheme/src/fun.c b/src/mzscheme/src/fun.c
index 033fcc4042..dda4bfc71a 100644
--- a/src/mzscheme/src/fun.c
+++ b/src/mzscheme/src/fun.c
@@ -4364,13 +4364,14 @@ static Scheme_Meta_Continuation *clone_meta_cont(Scheme_Meta_Continuation *mc,
       break;
     if (!mc->pseudo && SAME_OBJ(mc->prompt_tag, limit_tag))
       break;
-    if (for_composable && mc->pseudo && mc->empty_to_next && mc->next  
+    if (for_composable && mc->pseudo && mc->empty_to_next && mc->next
         && SAME_OBJ(mc->next->prompt_tag, limit_tag)) {
       /* We don't need to keep the compose-introduced
          meta-continuation, because it represents an empty
          continuation relative to the prompt. */
       break;
     }
+    
     naya = MALLOC_ONE_RT(Scheme_Meta_Continuation);
     cnt++;
     memcpy(naya, mc, sizeof(Scheme_Meta_Continuation));
@@ -4395,6 +4396,22 @@ static Scheme_Meta_Continuation *clone_meta_cont(Scheme_Meta_Continuation *mc,
           naya->cont_mark_stack_copied = NULL;
       }
       naya->cont_mark_pos_bottom = prompt->boundary_mark_pos;
+      {
+        Scheme_Cont *cnaya;
+        cnaya = MALLOC_ONE_TAGGED(Scheme_Cont);
+        memcpy(cnaya, naya->cont, sizeof(Scheme_Cont));
+
+        naya->cont = cnaya;
+
+        cnaya->cont_mark_total = naya->cont_mark_total;
+        cnaya->cont_mark_offset = naya->cont_mark_offset;
+        cnaya->cont_mark_pos_bottom = naya->cont_mark_pos_bottom;
+        cnaya->cont_mark_stack_copied = naya->cont_mark_stack_copied;
+
+        cnaya->prompt_stack_start = prompt->stack_boundary;
+
+        cnaya->need_meta_prompt = 1;
+      }
     } else {
       if (!mc->cm_caches) {
         mc->cm_shared = 1;
@@ -4433,6 +4450,23 @@ static Scheme_Meta_Continuation *clone_meta_cont(Scheme_Meta_Continuation *mc,
   return first;
 }
 
+static void sync_meta_cont(Scheme_Meta_Continuation *resume_mc)
+{
+  Scheme_Cont *cnaya;
+
+  cnaya = MALLOC_ONE_TAGGED(Scheme_Cont);
+  memcpy(cnaya, resume_mc->cont, sizeof(Scheme_Cont));
+    
+  resume_mc->cont = cnaya;
+    
+  cnaya->ss.cont_mark_stack += (resume_mc->cont_mark_total - cnaya->cont_mark_total);
+
+  cnaya->cont_mark_total = resume_mc->cont_mark_total;
+  cnaya->cont_mark_offset = resume_mc->cont_mark_offset;
+  cnaya->cont_mark_pos_bottom = resume_mc->cont_mark_pos_bottom;
+  cnaya->cont_mark_stack_copied = resume_mc->cont_mark_stack_copied;
+}
+
 void prune_cont_marks(Scheme_Meta_Continuation *resume_mc, Scheme_Cont *cont, Scheme_Object *extra_marks)
 {
   Scheme_Object *val;
@@ -4511,6 +4545,8 @@ void prune_cont_marks(Scheme_Meta_Continuation *resume_mc, Scheme_Cont *cont, Sc
       base++;
     }
   }
+
+  sync_meta_cont(resume_mc);
 }
 
 Scheme_Saved_Stack *clone_runstack_saved(Scheme_Saved_Stack *saved, Scheme_Object **boundary_start,
@@ -4808,7 +4844,10 @@ static void restore_continuation(Scheme_Cont *cont, Scheme_Thread *p, int for_pr
   } else {
     p->overflow = cont->save_overflow;
   }
-  if (!for_prompt) {
+  if (for_prompt) {
+    if (p->meta_prompt)
+      cont->need_meta_prompt = 1;
+  } else {
     Scheme_Meta_Continuation *mc, *resume_mc;
     if (resume) {
       resume_mc = MALLOC_ONE_RT(Scheme_Meta_Continuation);
@@ -4833,6 +4872,8 @@ static void restore_continuation(Scheme_Cont *cont, Scheme_Thread *p, int for_pr
         resume_mc->cont_mark_pos_bottom = cm_cont->cont_mark_pos_bottom;
         resume_mc->cont_mark_stack_copied = cm_cont->cont_mark_stack_copied;
 
+        resume_mc->cont = cm_cont;
+
         resume_mc->cm_caches = 1; /* conservative assumption */
 
         resume_mc->next = p->meta_continuation;
@@ -4949,8 +4990,11 @@ static void restore_continuation(Scheme_Cont *cont, Scheme_Thread *p, int for_pr
     MZ_CONT_MARK_STACK = 0;
   }
 
-  /* If there's a resume, then set up a meta prompt: */
-  if (resume) {
+  /* If there's a resume, then set up a meta prompt.
+     We also need a meta-prompt if we're returning from a composed
+     continuation to a continuation captured under a meta-prompt,
+     or truncated somewhere along the way. */
+  if (resume || (for_prompt && cont->need_meta_prompt)) {
     Scheme_Prompt *meta_prompt;
 
     meta_prompt = MALLOC_ONE_TAGGED(Scheme_Prompt);
@@ -5003,7 +5047,7 @@ static void restore_continuation(Scheme_Cont *cont, Scheme_Thread *p, int for_pr
     sub_conts = scheme_make_raw_pair((Scheme_Object *)sub_cont, sub_conts);
   }
 
-  if (!shortcut_prompt) {
+  if (!shortcut_prompt) {    
     Scheme_Cont *tc;
     for (tc = cont; tc->buf.cont; tc = tc->buf.cont) {
     }
@@ -5582,6 +5626,7 @@ Scheme_Object *scheme_finish_apply_for_prompt(Scheme_Prompt *prompt, Scheme_Obje
         p->cjs.val = val;
       }
       p->stack_start = resume->stack_start;
+      p->decompose = resume_mc->cont;
       scheme_longjmpup(&resume->jmp->cont);
       return NULL;
     }
@@ -5626,7 +5671,10 @@ static Scheme_Object *compose_continuation(Scheme_Cont *cont, int exec_chain,
   /* Grab a continuation so that we capture the current Scheme stack,
      etc.: */
   saved = grab_continuation(p, 1, 0, NULL, NULL, NULL, NULL, 0, NULL, NULL, NULL, 0);
-  
+
+  if (p->meta_prompt)
+    saved->prompt_stack_start = p->meta_prompt->stack_boundary;
+
   overflow = MALLOC_ONE_RT(Scheme_Overflow);
 #ifdef MZTAG_REQUIRED
   overflow->type = scheme_rt_overflow;
@@ -5639,11 +5687,15 @@ static Scheme_Object *compose_continuation(Scheme_Cont *cont, int exec_chain,
   jmp->type = scheme_rt_overflow_jmp;
 #endif
   overflow->jmp = jmp;
-        
+
+  saved->resume_to = overflow; /* used by eval to jump to current meta-continuation */
+  cont->use_next_cont = saved;
+  saved = NULL;
+  
   scheme_init_jmpup_buf(&overflow->jmp->cont);
   if (scheme_setjmpup(&overflow->jmp->cont, overflow->jmp, ADJUST_STACK_START(p->stack_start))) {
     /* Returning. (Jumped here from finish_apply_for_prompt,
-       scheme_compose_continuation, or scheme_eval.)
+       scheme_compose_continuation, scheme_eval, or start_child.)
        
        We can return for several reasons:
         1. We got a result value.
@@ -5661,6 +5713,9 @@ static Scheme_Object *compose_continuation(Scheme_Cont *cont, int exec_chain,
 
     p = scheme_current_thread;
 
+    saved = p->decompose;
+    p->decompose = NULL;
+
     if (!p->cjs.jumping_to_continuation) {
       /* Got a result: */
       v = p->cjs.val;
@@ -5681,7 +5736,7 @@ static Scheme_Object *compose_continuation(Scheme_Cont *cont, int exec_chain,
     restore_continuation(saved, p, 1, v, NULL, 0,
                          NULL, NULL,
                          NULL, 0, NULL,
-                         0, !p->cjs.jumping_to_continuation, 
+                         1, !p->cjs.jumping_to_continuation, 
                          NULL, NULL);
 
     p->meta_continuation = mc;
@@ -5710,6 +5765,7 @@ static Scheme_Object *compose_continuation(Scheme_Cont *cont, int exec_chain,
       reset_cjs(&p->cjs);
       /* The current meta-continuation may have changed since capture: */
       saved->meta_continuation = p->meta_continuation;
+      cont->use_next_cont = saved;
       /* Fall though to continuation application below. */
     } else {
       return v;
@@ -5719,8 +5775,6 @@ static Scheme_Object *compose_continuation(Scheme_Cont *cont, int exec_chain,
   scheme_current_thread->suspend_break++;
   
   /* Here's where we jump to the target: */
-  saved->resume_to = overflow; /* used by eval to jump to current meta-continuation */
-  cont->use_next_cont = saved;
   cont->resume_to = overflow;
   cont->empty_to_next_mc = (char)empty_to_next_mc;
   scheme_current_thread->stack_start = cont->prompt_stack_start;
@@ -6174,6 +6228,7 @@ Scheme_Object *scheme_compose_continuation(Scheme_Cont *cont, int num_rands, Sch
     p->cjs.is_escape = 1;
 
     p->stack_start = mc->overflow->stack_start;
+    p->decompose = mc->cont;
 
     scheme_longjmpup(&mc->overflow->jmp->cont);
     return NULL;
@@ -7460,6 +7515,7 @@ void scheme_apply_dw_in_meta(Scheme_Dynamic_Wind *dw, int post_part, int meta_de
     rest->cont_mark_total = 0;
     rest->cont_mark_offset = 0;
     rest->cont_mark_stack_copied = NULL;
+    sync_meta_cont(rest);
     rest = rest->next;
   }
 
@@ -7475,6 +7531,7 @@ void scheme_apply_dw_in_meta(Scheme_Dynamic_Wind *dw, int post_part, int meta_de
       rest->cont_mark_stack_copied = cp;
     } else
       rest->cont_mark_stack_copied = NULL;
+    sync_meta_cont(rest);
   }
 
   old_cac = scheme_continuation_application_count;
diff --git a/src/mzscheme/src/mzmark.c b/src/mzscheme/src/mzmark.c
index 1409bea36d..000259b5da 100644
--- a/src/mzscheme/src/mzmark.c
+++ b/src/mzscheme/src/mzmark.c
@@ -997,6 +997,7 @@ static int meta_cont_proc_MARK(void *p) {
   gcMARK(c->overflow);
   gcMARK(c->next);
   gcMARK(c->cont_mark_stack_copied);
+  gcMARK(c->cont);
 
   return
   gcBYTES_TO_WORDS(sizeof(Scheme_Meta_Continuation));
@@ -1009,6 +1010,7 @@ static int meta_cont_proc_FIXUP(void *p) {
   gcFIXUP(c->overflow);
   gcFIXUP(c->next);
   gcFIXUP(c->cont_mark_stack_copied);
+  gcFIXUP(c->cont);
 
   return
   gcBYTES_TO_WORDS(sizeof(Scheme_Meta_Continuation));
@@ -1596,6 +1598,7 @@ static int thread_val_MARK(void *p) {
   gcMARK(pr->t_set_prev);
 
   MARK_cjs(&pr->cjs);
+  gcMARK(pr->decompose);
 
   gcMARK(pr->cell_values);
   gcMARK(pr->init_config);
@@ -1696,6 +1699,7 @@ static int thread_val_FIXUP(void *p) {
   gcFIXUP(pr->t_set_prev);
 
   FIXUP_cjs(&pr->cjs);
+  gcFIXUP(pr->decompose);
 
   gcFIXUP(pr->cell_values);
   gcFIXUP(pr->init_config);
@@ -3116,6 +3120,7 @@ static int mark_rb_node_SIZE(void *p) {
 static int mark_rb_node_MARK(void *p) {
   RBNode *rb = (RBNode *)p;
 
+  /* Short-circuit on NULL pointers, which are especially likely */
   if (rb->left) {
     gcMARK(rb->left);
   }
@@ -3132,6 +3137,7 @@ static int mark_rb_node_MARK(void *p) {
 static int mark_rb_node_FIXUP(void *p) {
   RBNode *rb = (RBNode *)p;
 
+  /* Short-circuit on NULL pointers, which are especially likely */
   if (rb->left) {
     gcFIXUP(rb->left);
   }
diff --git a/src/mzscheme/src/mzmarksrc.c b/src/mzscheme/src/mzmarksrc.c
index 146879394a..eb032856cd 100644
--- a/src/mzscheme/src/mzmarksrc.c
+++ b/src/mzscheme/src/mzmarksrc.c
@@ -381,6 +381,7 @@ meta_cont_proc {
   gcMARK(c->overflow);
   gcMARK(c->next);
   gcMARK(c->cont_mark_stack_copied);
+  gcMARK(c->cont);
 
  size:
   gcBYTES_TO_WORDS(sizeof(Scheme_Meta_Continuation));
@@ -610,6 +611,7 @@ thread_val {
   gcMARK(pr->t_set_prev);
 
   MARK_cjs(&pr->cjs);
+  gcMARK(pr->decompose);
 
   gcMARK(pr->cell_values);
   gcMARK(pr->init_config);
diff --git a/src/mzscheme/src/schpriv.h b/src/mzscheme/src/schpriv.h
index 87af3b37bc..d5b6594d2b 100644
--- a/src/mzscheme/src/schpriv.h
+++ b/src/mzscheme/src/schpriv.h
@@ -1065,7 +1065,7 @@ typedef struct Scheme_Dynamic_Wind {
 
 typedef struct Scheme_Cont {
   Scheme_Object so;
-  char composable, has_prompt_dw;
+  char composable, has_prompt_dw, need_meta_prompt;
   struct Scheme_Meta_Continuation *meta_continuation;
   Scheme_Jumpup_Buf buf;
   Scheme_Dynamic_Wind *dw;
@@ -1179,6 +1179,8 @@ typedef struct Scheme_Meta_Continuation {
   MZ_MARK_POS_TYPE cont_mark_pos;
   long cont_mark_total, cont_mark_offset;
   Scheme_Cont_Mark *cont_mark_stack_copied;
+  /* Continuation (whose cont-mark info is the same as above) */
+  struct Scheme_Cont *cont;
   /* Next: */
   struct Scheme_Meta_Continuation *next;
 } Scheme_Meta_Continuation;
diff --git a/src/mzscheme/src/thread.c b/src/mzscheme/src/thread.c
index 9ee76d7270..8860d64b1b 100644
--- a/src/mzscheme/src/thread.c
+++ b/src/mzscheme/src/thread.c
@@ -2784,10 +2784,13 @@ static void start_child(Scheme_Thread * volatile child,
       if (!SAME_OBJ(p->meta_continuation->prompt_tag, scheme_default_prompt_tag)) {
         scheme_signal_error("thread ended with meta continuation that isn't for the default prompt");
       } else {
-        oflow = p->meta_continuation->overflow;
-        p->meta_continuation = p->meta_continuation->next;
+        Scheme_Meta_Continuation *mc;
+        mc = p->meta_continuation;
+        oflow = mc->overflow;
+        p->meta_continuation = mc->next;
         if (!oflow->eot) {
           p->stack_start = oflow->stack_start;
+          p->decompose = mc->cont;
           scheme_longjmpup(&oflow->jmp->cont);
         }
       }