diff --git a/plugins/keyboard/gsd-keyboard-xkb.c b/plugins/keyboard/gsd-keyboard-xkb.c
index 346fdba..19ae642 100644
--- a/plugins/keyboard/gsd-keyboard-xkb.c
+++ b/plugins/keyboard/gsd-keyboard-xkb.c
@@ -158,18 +158,42 @@ 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, g_strcmp0);
+
+		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);
+
 			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);
 	}