diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index a70598bb6c9..6b4446a0be8 100644
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -285,7 +285,7 @@ widget-choose
   ;; Apply quote substitution to customize choice menu item text,
   ;; whether it occurs in a widget buffer or in a popup menu.
   (let ((items (mapc (lambda (x)
-                       (when (consp x)
+                       (when (proper-list-p x)
                          (dotimes (i (1- (length x)))
                            (when (stringp (nth i x))
                              (setcar (nthcdr i x)