diff --git a/collects/macro-debugger/view/debug-format.ss b/collects/macro-debugger/view/debug-format.ss
index 07c938a..87cdc04 100644
--- a/collects/macro-debugger/view/debug-format.ss
+++ b/collects/macro-debugger/view/debug-format.ss
@@ -7,13 +7,15 @@
 (define (write-debug-file file exn events)
   (with-output-to-file file
     (lambda ()
-      (write `(list ,@(map (lambda (e) (serialize-datum e)) events)))
+      (pretty-print
+       `(list ,@(map (lambda (e) (serialize-datum e)) events)))
       (newline)
       (write (exn-message exn))
       (newline)
-      (write (map serialize-context-frame
-                  (continuation-mark-set->context
-                   (exn-continuation-marks exn)))))
+      (pretty-print
+       (map serialize-context-frame
+            (continuation-mark-set->context
+             (exn-continuation-marks exn)))))
     #:exists 'replace))
 
 (define (serialize-datum d)
diff --git a/collects/macro-debugger/view/step-display.ss b/collects/macro-debugger/view/step-display.ss
index 65be319..075c0d1 100644
--- a/collects/macro-debugger/view/step-display.ss
+++ b/collects/macro-debugger/view/step-display.ss
@@ -119,17 +119,15 @@
     (define/private (show-lctx step shift-table)
       (define state (protostep-s1 step))
       (define lctx (state-lctx state))
-      (when (pair? lctx)
-        (send: sbview sb:syntax-browser<%> add-text "\n")
-        (for ([bf (reverse lctx)])
-          (send: sbview sb:syntax-browser<%> add-text 
-                 "while executing macro transformer in:\n")
-          (insert-syntax/redex (bigframe-term bf)
-                               (bigframe-foci bf)
-                               (state-binders state)
-                               shift-table
-                               (state-uses state)
-                               (state-frontier state)))))
+      (for ([bf lctx])
+        (send: sbview sb:syntax-browser<%> add-text 
+               "\nwhile executing macro transformer in:\n")
+        (insert-syntax/redex (bigframe-term bf)
+                             (bigframe-foci bf)
+                             (state-binders state)
+                             shift-table
+                             (state-uses state)
+                             (state-frontier state))))
 
     ;; separator : Step -> void
     (define/private (separator step)
diff --git a/collects/macro-debugger/view/term-record.ss b/collects/macro-debugger/view/term-record.ss
index fe404ad..1839dfd 100644
--- a/collects/macro-debugger/view/term-record.ss
+++ b/collects/macro-debugger/view/term-record.ss
@@ -275,7 +275,11 @@
 
     ;; display-initial-term : -> void
     (define/public (display-initial-term)
-      (send: displayer step-display<%> add-syntax (wderiv-e1 deriv)))
+      (cond [raw-deriv-oops
+             (send: displayer step-display<%> add-internal-error
+                    "derivation" raw-deriv-oops #f events)]
+            [else
+             (send: displayer step-display<%> add-syntax (wderiv-e1 deriv))]))
 
     ;; display-final-term : -> void
     (define/public (display-final-term)