[libdazzle] preferences: hide all subpages when changing pages

[Christian Hergert <chergert src gnome org>]

commit 28eff52a2ab77ca0b0e62e071dd04e70eacd2db1
Author: Christian Hergert <chergert redhat com>
Date:   Thu Aug 8 19:48:24 2019 -0700

    preferences: hide all subpages when changing pages
    
    This is useful so that if there are no visible widgets in the sub-page,
    we don't show another subpage instead.

 src/prefs/dzl-preferences-view.c | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/src/prefs/dzl-preferences-view.c b/src/prefs/dzl-preferences-view.c
index 51cb746..3ee764a 100644
--- a/src/prefs/dzl-preferences-view.c
+++ b/src/prefs/dzl-preferences-view.c
@@ -454,6 +454,7 @@ dzl_preferences_view_add_page (DzlPreferences *preferences,
     return;
 
   page = g_object_new (DZL_TYPE_PREFERENCES_PAGE,
+                       "name", page_name,
                        "priority", priority,
                        "visible", TRUE,
                        NULL);
@@ -994,8 +995,12 @@ dzl_preferences_view_set_page (DzlPreferences *preferences,
 
   if (strchr (page_name, '.') != NULL)
     {
+      gtk_container_foreach (GTK_CONTAINER (priv->subpage_stack),
+                             (GtkCallback)gtk_widget_hide,
+                             NULL);
       dzl_preferences_page_set_map (DZL_PREFERENCES_PAGE (page), map);
       gtk_stack_set_visible_child (priv->subpage_stack, page);
+      gtk_widget_show (page);
       gtk_widget_show (GTK_WIDGET (priv->subpage_stack));
     }
   else