diff --git a/src/screen.c b/src/screen.c
index 53343e8..d72d779 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -1078,7 +1078,9 @@
 		+ wp->w_height + wp->w_popup_padding[2] + wp->w_popup_border[2];
 	popup_attr = get_wcr_attr(wp);
 
-	if (enc_utf8)
+	// We can only use these line drawing characters when 'encoding' is
+	// "utf-8" and 'ambiwidth' is "single".
+	if (enc_utf8 && p_ambw == 's')
 	{
 	    border_char[0] = border_char[2] = 0x2550;
 	    border_char[1] = border_char[3] = 0x2551;
diff --git a/src/version.c b/src/version.c
index 53a2644..accea72 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1459,
+/**/
     1458,
 /**/
     1457,