diff --git a/editor/editor.lisp b/editor/editor.lisp
index 4801c16..91ba88d 100644
--- a/editor/editor.lisp
+++ b/editor/editor.lisp
@@ -424,7 +424,7 @@ serial connection the editor normally runs under.")
          (move-cursor (view-line-number (buffer-view buffer) line) char-pos)
          (write-char (aref (line-content line) char-pos) *eio*)
          (update-buffer-cursor buffer)))
-      (t
+      ((line-in-view line (buffer-view buffer))
        (hide-cursor)
        (move-cursor (view-line-number (buffer-view buffer) line) start)
        (write-byte #x1B *eio*)
@@ -432,7 +432,9 @@ serial connection the editor normally runs under.")
        (write-char #\K *eio*)
        (write-string (line-content line) *eio* :start start)
        (update-buffer-cursor buffer)
-       (show-cursor))))
+       (show-cursor))
+      (t
+       (warn "Tried to redisplay an off-screen line."))))
   (force-output *eio*))