Fix window button updates in split headers

We were only updating window buttons when the headerbar was
a direct child of the window. That is not the case in more
complicated situations, such as the split headers in gedit
or polari. To fix such cases, make the headerbar itself listen
for state changes on its toplevel.

https://bugzilla.gnome.org/show_bug.cgi?id=747805

diff --git a/gtk/gtkheaderbar.c b/gtk/gtkheaderbar.c
index f2f287858f788dcafd363bb8e10b0746a375f363..bf9529530ebbb47d98535d397b1ccd6a07999fc4 100644 (file)
--- a/gtk/gtkheaderbar.c
+++ b/gtk/gtkheaderbar.c
@@ -1812,6 +1812,36 @@ gtk_header_bar_unrealize (GtkWidget *widget)
   GTK_WIDGET_CLASS (gtk_header_bar_parent_class)->unrealize (widget);
 }
 
+static gboolean
+window_state_changed (GtkWidget           *window,
+                      GdkEventWindowState *event,
+                      gpointer             data)
+{
+  GtkHeaderBar *bar = GTK_HEADER_BAR (data);
+
+  if (event->changed_mask & (GDK_WINDOW_STATE_FULLSCREEN | GDK_WINDOW_STATE_MAXIMIZED | GDK_WINDOW_STATE_TILED))
+    _gtk_header_bar_update_window_buttons (bar);
+
+  return FALSE;
+}
+
+static void
+gtk_header_bar_hierarchy_changed (GtkWidget *widget,
+                                  GtkWidget *previous_toplevel)
+{
+  GtkWidget *toplevel;
+
+  toplevel = gtk_widget_get_toplevel (widget);
+
+  if (previous_toplevel)
+    g_signal_handlers_disconnect_by_func (previous_toplevel,
+                                          window_state_changed, widget);
+
+  if (toplevel)
+    g_signal_connect_after (toplevel, "window-state-event",
+                            G_CALLBACK (window_state_changed), widget);
+}
+
 static void
 gtk_header_bar_class_init (GtkHeaderBarClass *class)
 {
@@ -1831,6 +1861,7 @@ gtk_header_bar_class_init (GtkHeaderBarClass *class)
   widget_class->draw = gtk_header_bar_draw;
   widget_class->realize = gtk_header_bar_realize;
   widget_class->unrealize = gtk_header_bar_unrealize;
+  widget_class->hierarchy_changed = gtk_header_bar_hierarchy_changed;
 
   container_class->add = gtk_header_bar_add;
   container_class->remove = gtk_header_bar_remove;