diff --git a/src/undo.c b/src/undo.c
index 7abd67b..5ebf0e7 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -2710,7 +2710,7 @@
 
 	FOR_ALL_WINDOWS(wp)
 	{
-	    if (wp->w_buffer == curbuf && wp->w_p_conceal)
+	    if (wp->w_buffer == curbuf && wp->w_p_conc > 0)
 		redraw_win_later(wp, NOT_VALID);
 	}
     }