Update runtime files
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 0b35e94..9141763 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -799,7 +799,8 @@
 	When on, Vim will change the current working directory whenever you
 	open a file, switch buffers, delete a buffer or open/close a window.
 	It will change to the directory containing the file which was opened
-	or selected.
+	or selected.  When a buffer has no name it also has no directory, thus
+	the current directory won't change when navigating to it.
 	Note: When this option is on some plugins may not work.
 
 			*'autoshelldir'* *'asd'* *'noautoshelldir'* *'noasd'*