diff --git a/collects/stepper/private/model.ss b/collects/stepper/private/model.ss
index 9ade4872b1..7748eb976f 100644
--- a/collects/stepper/private/model.ss
+++ b/collects/stepper/private/model.ss
@@ -293,8 +293,8 @@
       (program-expander
        (lambda () 
          ; swap these to allow errors to escape (e.g., when debugging)
-         #;(error-display-handler err-display-handler)
-         (void)
+         (error-display-handler err-display-handler)
+         #;(void)
          )
        (lambda (expanded continue-thunk) ; iter
          (if (eof-object? expanded)