Index: gnome-settings-daemon-2.27.4/plugins/keyboard/gsd-keyboard-xkb.c
===================================================================
--- gnome-settings-daemon-2.27.4.orig/plugins/keyboard/gsd-keyboard-xkb.c
+++ gnome-settings-daemon-2.27.4/plugins/keyboard/gsd-keyboard-xkb.c
@@ -137,6 +137,103 @@ apply_desktop_settings (void)
 	gkbd_desktop_config_activate (&current_config);
 }
 
+#define GROUP_SWITCHERS_GROUP "grp"
+#define DEFAULT_GROUP_SWITCH "grp:shifts_toggle"
+
+static void
+_maybe_add_layout_switcher (GSList      *layouts,
+                            GConfClient *conf_client)
+{
+        GSList   *options;
+        GSList   *option;
+        gboolean  any_switcher;
+
+        /* do we have more than one layout? */
+        if (g_slist_length (layouts) > 1)
+                return;
+
+        /* If yes, we need to make sure there's a way to change the layout
+         * Based on xkl_layout_chooser_add_default_switcher_if_necessary() in
+         * capplets/keyboard/gnome-keyboard-properties-xkbltadd.c
+         * (gnome-control-center) */
+        options = gconf_client_get_list (conf_client,
+                                         GKBD_KEYBOARD_CONFIG_KEY_OPTIONS,
+                                         GCONF_VALUE_STRING,
+                                         NULL);    
+
+        if (options == NULL) {
+                /* nothing in gconf, get the current options from X */
+                GkbdKeyboardConfig kbd_config;
+
+                gkbd_keyboard_config_init (&kbd_config,
+                                           conf_client,
+                                           xkl_engine);
+                gkbd_keyboard_config_load_from_x_initial (&kbd_config, NULL);
+
+                for (option = kbd_config.options; option != NULL; option = option->next) {
+                        options = g_slist_prepend (options,
+                                                   g_strdup (option->data));
+                }
+
+                options = g_slist_reverse (options);
+
+                gkbd_keyboard_config_term (&kbd_config);
+        }
+
+        any_switcher = FALSE;
+
+        while (option != NULL) {
+                char *g, *o;
+
+                if (gkbd_keyboard_config_split_items (option->data, &g, &o)) {
+                        if (!g_ascii_strcasecmp (g, GROUP_SWITCHERS_GROUP)) {
+                                any_switcher = TRUE;
+                                break;
+                        }
+                }
+                option = option->next;
+        }
+
+        /* no option to switch between layouts, let's add one */
+        if (!any_switcher) {
+                XklConfigItem *ci = xkl_config_item_new ();
+
+                g_snprintf (ci->name, XKL_MAX_CI_NAME_LENGTH,
+                            DEFAULT_GROUP_SWITCH);
+
+                /* we make sure the option we want to add is known */
+                if (!xkl_registry) {
+                        xkl_registry = xkl_config_registry_get_instance (xkl_engine);
+                        if (!xkl_config_registry_load (xkl_registry, TRUE)) {
+                                g_object_unref (xkl_registry);
+                                xkl_registry = NULL;
+                        }
+                }
+
+                if (xkl_registry &&
+                    xkl_config_registry_find_option (xkl_registry,
+                                                     GROUP_SWITCHERS_GROUP,
+                                                     ci)) {
+                        const char *id;
+                        
+                        id = gkbd_keyboard_config_merge_items
+                                            (GROUP_SWITCHERS_GROUP,
+                                             DEFAULT_GROUP_SWITCH);
+
+                        options = g_slist_append (options, g_strdup (id));
+                        gconf_client_set_list (conf_client,
+                                               GKBD_KEYBOARD_CONFIG_KEY_OPTIONS,
+                                               GCONF_VALUE_STRING, options,
+                                               NULL);
+                }
+
+                g_object_unref (G_OBJECT (ci));
+        }
+
+        g_slist_foreach (options, (GFunc) g_free, NULL);
+        g_slist_free (options);
+}
+
 static gboolean
 try_activating_xkb_config_if_new (GkbdKeyboardConfig *current_sys_kbd_config)
 {
@@ -211,6 +308,38 @@ filter_xkb_config (void)
 	return any_change;
 }
 
+static int
+_xkb_layout_strcmp (const char *a,
+                    const char *b)
+{
+        char *layout_a;
+        char *layout_b;
+        char *p;
+        int   ret;
+
+        if (!a)
+                return -(a != b);
+        if (!b)
+                return (a != b);
+
+        layout_a = g_strdup (a);
+        p = strchr (layout_a, '\t');
+        if (p != NULL)
+                p[0] = '\0';
+
+        layout_b = g_strdup (b);
+        p = strchr (layout_b, '\t');
+        if (p != NULL)
+                p[0] = '\0';
+
+        ret = strcmp (layout_a, layout_b);
+
+        g_free (layout_a);
+        g_free (layout_b);
+
+        return ret;
+}
+
 static void
 apply_xkb_settings (void)
 {
@@ -233,18 +362,44 @@ apply_xkb_settings (void)
 	gdm_keyboard_layout = NULL;
 	if (gdm_layout != NULL) {
 		GSList *layouts;
+		GSList *found_node;
+
 		layouts = gconf_client_get_list (conf_client,
 						 GKBD_KEYBOARD_CONFIG_KEY_LAYOUTS,
 						 GCONF_VALUE_STRING, NULL);
-		if (layouts == NULL) {
-			layouts =
-			    g_slist_append (layouts,
-					    g_strdup (gdm_layout));
+
+		/* Add the layout if it doesn't already exist. XKB limits the
+		 * total number of layouts to four. If we already have four
+		 * layouts configured, we replace the last one. This prevents the
+		 * list from becoming full if the user has a habit of selecting
+		 * many different keyboard layouts in GDM. */
+
+		found_node = g_slist_find_custom (layouts, gdm_layout, _xkb_layout_strcmp);
+
+		if (found_node) {
+			if (g_slist_position (layouts, found_node) > 3) {
+				/* If the layout we found appears after the
+				 * fourth entry, we move it up to fourth place.
+				 * Otherwise, XKB will not activate it. */
+				g_free (found_node->data);
+				layouts = g_slist_delete_link (layouts, found_node);
+				found_node = NULL;
+			}
+		}
+
+		if (!found_node) {
+			/* Insert in fourth slot or at the end of list,
+			 * whichever comes first */
+			layouts = g_slist_insert (layouts, g_strdup (gdm_layout), 3);
+
+			_maybe_add_layout_switcher (layouts, conf_client);
+
 			gconf_client_set_list (conf_client,
 					       GKBD_KEYBOARD_CONFIG_KEY_LAYOUTS,
 					       GCONF_VALUE_STRING, layouts,
 					       NULL);
 		}
+
 		g_slist_foreach (layouts, (GFunc) g_free, NULL);
 		g_slist_free (layouts);
 	}