[gtk+/gtk-3-16] GtkListBox: Listen for adjustment changes

[Matthias Clasen <matthiasc src gnome org>]

commit 6978db3a52a5cb3b3eca17a7569f432bce87ca1f
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Jul 19 22:08:36 2015 -0400

    GtkListBox: Listen for adjustment changes
    
    We automatically pick up an adjustment from our parent
    scrollable, but we failed to update it when it changes.
    This is happening in the places sidebar, and it was causing
    the focus-tracking to fail there, letting the focus move
    out of view. With this change, the focus remains visible.

 gtk/gtklistbox.c |   27 +++++++++++++++++++++++----
 1 files changed, 23 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtklistbox.c b/gtk/gtklistbox.c
index d152439..03ebd0d 100644
--- a/gtk/gtklistbox.c
+++ b/gtk/gtklistbox.c
@@ -948,8 +948,10 @@ gtk_list_box_set_adjustment (GtkListBox    *box,
   GtkListBoxPrivate *priv = BOX_PRIV (box);
 
   g_return_if_fail (GTK_IS_LIST_BOX (box));
+  g_return_if_fail (adjustment == NULL || GTK_IS_ADJUSTMENT (adjustment));
 
-  g_object_ref_sink (adjustment);
+  if (adjustment)
+    g_object_ref_sink (adjustment);
   if (priv->adjustment)
     g_object_unref (priv->adjustment);
   priv->adjustment = adjustment;
@@ -975,19 +977,36 @@ gtk_list_box_get_adjustment (GtkListBox *box)
 }
 
 static void
+adjustment_changed (GObject    *object,
+                    GParamSpec *pspec,
+                    gpointer    data)
+{
+  GtkAdjustment *adjustment;
+
+  adjustment = gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (object));
+  gtk_list_box_set_adjustment (GTK_LIST_BOX (data), adjustment);
+}
+
+static void
 gtk_list_box_parent_set (GtkWidget *widget,
                          GtkWidget *prev_parent)
 {
   GtkWidget *parent;
-  GtkAdjustment *adjustment;
 
   parent = gtk_widget_get_parent (widget);
 
+  if (prev_parent && GTK_IS_SCROLLABLE (prev_parent))
+    g_signal_handlers_disconnect_by_func (prev_parent,
+                                          G_CALLBACK (adjustment_changed), widget);
+
   if (parent && GTK_IS_SCROLLABLE (parent))
     {
-      adjustment = gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (parent));
-      gtk_list_box_set_adjustment (GTK_LIST_BOX (widget), adjustment);
+      adjustment_changed (G_OBJECT (parent), NULL, widget);
+      g_signal_connect (parent, "notify::vadjustment",
+                        G_CALLBACK (adjustment_changed), widget);
     }
+  else
+    gtk_list_box_set_adjustment (GTK_LIST_BOX (widget), NULL);
 }
 
 /**