diff --git a/lisp/cus-start.el b/lisp/cus-start.el
index 7786d349709..a1377435147 100644
--- a/lisp/cus-start.el
+++ b/lisp/cus-start.el
@@ -287,7 +287,7 @@ since it could result in memory overflow and make Emacs crash."
 	     (scroll-margin windows integer)
 	     (hscroll-margin windows integer "22.1")
 	     (hscroll-step windows number "22.1")
-	     (truncate-partial-width-windows display boolean)
+	     (truncate-partial-width-windows display boolean "23.1")
 	     (mode-line-inverse-video mode-line boolean)
 	     (mode-line-in-non-selected-windows mode-line boolean "22.1")
 	     (line-number-display-limit display