[libgd] header-bar: add a piece of documentation

[Cosimo Cecchi <cosimoc src gnome org>]

commit 499ee2467f755a528d947250a99cfc73d97f8607
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Tue Feb 19 19:46:24 2013 -0500

    header-bar: add a piece of documentation

 libgd/gd-header-bar.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/libgd/gd-header-bar.c b/libgd/gd-header-bar.c
index 1c329bd..7f5f43f 100644
--- a/libgd/gd-header-bar.c
+++ b/libgd/gd-header-bar.c
@@ -572,7 +572,8 @@ gd_header_bar_get_title (GdHeaderBar *bar)
  *
  * Sets a custom title for the #GdHeaderBar. The title should help a
  * user identify the current view. This supercedes any title set by
- * gd_header_bar_set_title()
+ * gd_header_bar_set_title(). You should set the custom title to %NULL,
+ * for the header title label to be visible again.
  *
  **/
 void