[gtk+/gtk-3-22] gtkwindow: Hide CSD title bar when undecorated

[Olivier Fourdan <ofourdan src gnome org>]

commit 5209995171e4f322ab6732d6b58589608bf97755
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Wed May 3 14:29:18 2017 +0200

    gtkwindow: Hide CSD title bar when undecorated
    
    When switching from decorated to undecorated, the title bar should be
    hidden as well.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=782117

 gtk/gtkwindow.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 55924bb..b5d6498 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -6015,7 +6015,8 @@ update_csd_visibility (GtkWindow *window)
   if (priv->title_box == NULL)
     return FALSE;
 
-  visible = !priv->fullscreen &&
+  visible = priv->decorated &&
+            !priv->fullscreen &&
             !(priv->titlebar == priv->title_box &&
               priv->maximized &&
               priv->hide_titlebar_when_maximized);