diff --git a/collects/macro-debugger/syntax-browser/display.ss b/collects/macro-debugger/syntax-browser/display.ss
index 6d551b1..9fe40f8 100644
--- a/collects/macro-debugger/syntax-browser/display.ss
+++ b/collects/macro-debugger/syntax-browser/display.ss
@@ -51,7 +51,7 @@
           (base-style (standard-font text config))
           (start-position insertion-point)
           (end-position (+ insertion-point output-length))))
-   (send text begin-edit-sequence)
+   (send text begin-edit-sequence #f)
    (define **editing (now))
    (send text insert output-length output-string insertion-point)
    (define **inserted (now))
@@ -110,7 +110,7 @@
     (define/public (refresh)
       (with-unlock text
         (send* text 
-          (begin-edit-sequence)
+          (begin-edit-sequence #f)
           (change-style unhighlight-d start-position end-position))
         (apply-extra-styles)
         (let ([selected-syntax
diff --git a/collects/macro-debugger/syntax-browser/pretty-printer.ss b/collects/macro-debugger/syntax-browser/pretty-printer.ss
index a6e3e52..1295390 100644
--- a/collects/macro-debugger/syntax-browser/pretty-printer.ss
+++ b/collects/macro-debugger/syntax-browser/pretty-printer.ss
@@ -29,13 +29,15 @@
     (let-values ([(line column position) (port-next-location port)])
       (sub1 position)))
   (define (pp-pre-hook obj port)
-    (send range-builder push! obj (current-position))
+    (when (flat=>stx obj)
+      (send range-builder push! (current-position)))
     (send range-builder set-start obj (current-position)))
   (define (pp-post-hook obj port)
-    (send range-builder pop! (flat=>stx obj) (current-position))
+    (define stx (flat=>stx obj))
+    (when stx
+      (send range-builder pop! stx (current-position)))
     (let ([start (send range-builder get-start obj)]
-          [end (current-position)]
-          [stx (flat=>stx obj)])
+          [end (current-position)])
       (when (and start stx)
         (send range-builder add-range stx (cons start end)))))
   (define (pp-extend-style-table identifier-list)
@@ -132,7 +134,7 @@
     (define saved-starts null)
     (define saved-subss null)
 
-    (define/public (push! obj start)
+    (define/public (push! start)
       (set! saved-starts (cons working-start saved-starts))
       (set! saved-subss (cons working-subs saved-subss))
       (set! working-start start)
@@ -182,5 +184,3 @@
            (>= (- (range-end x) (range-start x))
                (- (range-end y) (range-start y)))))))
     ))
-
-  
diff --git a/collects/macro-debugger/syntax-browser/properties.ss b/collects/macro-debugger/syntax-browser/properties.ss
index 2d84de3..63176ba 100644
--- a/collects/macro-debugger/syntax-browser/properties.ss
+++ b/collects/macro-debugger/syntax-browser/properties.ss
@@ -43,7 +43,7 @@
     (define/public (refresh)
       (send* text
         (lock #f)
-        (begin-edit-sequence)
+        (begin-edit-sequence #f)
         (erase))
       (if (syntax? selected-syntax)
           (refresh/mode mode)
diff --git a/collects/macro-debugger/view/stepper.ss b/collects/macro-debugger/view/stepper.ss
index b833438..1226e11 100644
--- a/collects/macro-debugger/view/stepper.ss
+++ b/collects/macro-debugger/view/stepper.ss
@@ -309,7 +309,7 @@
       (define text (send: sbview sb:syntax-browser<%> get-text))
       (define position-of-interest 0)
       (define multiple-terms? (> (length (cursor->list terms)) 1))
-      (send text begin-edit-sequence)
+      (send text begin-edit-sequence #f)
       (send: sbview sb:syntax-browser<%> erase-all)
 
       (update:show-prefix)