diff --git a/collects/drracket/private/syncheck/gui.rkt b/collects/drracket/private/syncheck/gui.rkt
index f77ce27e48..245e34747a 100644
--- a/collects/drracket/private/syncheck/gui.rkt
+++ b/collects/drracket/private/syncheck/gui.rkt
@@ -1582,6 +1582,7 @@ If the namespace does not, they are colored the unbound color.
             (send (send defs-text get-tab) add-bkg-running-color 'syncheck "orchid" cs-syncheck-running)
             (send defs-text syncheck:init-arrows)
             (let loop ([val val]
+                       [start-time (current-inexact-milliseconds)]
                        [i 0])
               (cond
                 [(null? val)
@@ -1589,15 +1590,17 @@ If the namespace does not, they are colored the unbound color.
                  (send defs-text syncheck:update-drawn-arrows)
                  (send (send defs-text get-tab) remove-bkg-running-color 'syncheck)
                  (set-syncheck-running-mode #f)]
-                [(= i 500)
+                [(and (i . > . 0)  ;; check i just in case things are really strange
+                      (20 . <= . (- (current-inexact-milliseconds) start-time)))
                  (queue-callback
                   (λ ()
                     (when (unbox bx)
-                      (log-timeline "continuing replay-compile-comp-trace" (loop val 0))))
+                      (log-timeline "continuing replay-compile-comp-trace"
+                                    (loop val (current-inexact-milliseconds) 0))))
                   #f)]
                 [else
                  (process-trace-element defs-text (car val))
-                 (loop (cdr val) (+ i 1))]))))
+                 (loop (cdr val) start-time (+ i 1))]))))
         
         (define/private (process-trace-element defs-text x)
           ;; using 'defs-text' all the time is wrong in the case of embedded editors,
diff --git a/collects/drracket/private/syncheck/traversals.rkt b/collects/drracket/private/syncheck/traversals.rkt
index abcb575df8..7675316bb6 100644
--- a/collects/drracket/private/syncheck/traversals.rkt
+++ b/collects/drracket/private/syncheck/traversals.rkt
@@ -1134,10 +1134,22 @@
                                   (for/or ([(level id-set) (in-hash phase-to-map)])
                                     (get-ids id-set new-id))))))))
                       #t))
-               (send defs-text syncheck:add-rename-menu
-                     id-as-sym
-                     loc-lst
-                     name-dup?)))))))
+               (define max-to-send-at-once 30)
+               (let loop ([loc-lst loc-lst]
+                          [len (length loc-lst)])
+                 (cond
+                   [(<= len max-to-send-at-once)
+                    (send defs-text syncheck:add-rename-menu
+                          id-as-sym
+                          loc-lst
+                          name-dup?)]
+                   [else
+                    (send defs-text syncheck:add-rename-menu
+                          id-as-sym
+                          (take loc-lst max-to-send-at-once)
+                          name-dup?)
+                    (loop (drop loc-lst max-to-send-at-once)
+                          (- len max-to-send-at-once))]))))))))
     
     ;; remove-duplicates-stx : (listof syntax[original]) -> (listof syntax[original])
     ;; removes duplicates, based on the source locations of the identifiers