diff --git a/collects/macro-debugger/syntax-browser/widget.ss b/collects/macro-debugger/syntax-browser/widget.ss
index 3b0a36b..d202d2e 100644
--- a/collects/macro-debugger/syntax-browser/widget.ss
+++ b/collects/macro-debugger/syntax-browser/widget.ss
@@ -196,7 +196,7 @@
             )
           display)))
 
-    (define/private (calculate-columns)
+    (define/public (calculate-columns)
       (define style (code-style -text (send config get-syntax-font-size)))
       (define char-width (send style get-text-width (send -ecanvas get-dc)))
       (define-values (canvas-w canvas-h) (send -ecanvas get-client-size))
diff --git a/collects/macro-debugger/view/frame.ss b/collects/macro-debugger/view/frame.ss
index 29688ba..4cd2f15 100644
--- a/collects/macro-debugger/view/frame.ss
+++ b/collects/macro-debugger/view/frame.ss
@@ -54,6 +54,7 @@
     (define/override (on-size w h)
       (send config set-width w)
       (send config set-height h)
+      (send config set-columns (send (send widget get-view) calculate-columns))
       (send widget update/preserve-view))
 
     (define warning-panel