diff --git a/src/popupwin.c b/src/popupwin.c
index 3b808e2..e1c21ac 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -611,7 +611,7 @@
     int	    sign_id = 0;
     char_u  *sign_name = popup_get_sign_name(wp);
 
-    buf_delete_signs(wp->w_buffer, (char_u *)"popupmenu");
+    buf_delete_signs(wp->w_buffer, (char_u *)"PopUpMenu");
 
     if ((wp->w_popup_flags & POPF_CURSORLINE) != 0)
     {
@@ -626,7 +626,7 @@
 	    sign_define_by_name(sign_name, NULL, (char_u *)linehl, NULL, NULL);
 	}
 
-	sign_place(&sign_id, (char_u *)"popupmenu", sign_name,
+	sign_place(&sign_id, (char_u *)"PopUpMenu", sign_name,
 			       wp->w_buffer, wp->w_cursor.lnum, SIGN_DEF_PRIO);
 	redraw_win_later(wp, NOT_VALID);
     }