Consistently use . Fixes failing test

src/converse-controlbox.js

@@ -101,12 +101,10 @@
                 },
 
                 onChatBoxesFetched: function (collection, resp) {
+                    var _converse = this.__super__._converse;
                     this.__super__.onChatBoxesFetched.apply(this, arguments);
-                    if (!_.includes(_.map(resp, 'id'), 'controlbox')) {
-                        this.add({
-                            id: 'controlbox',
-                            box_id: 'controlbox'
-                        });
+                    if (!_.includes(_.map(collection, 'id'), 'controlbox')) {
+                        _converse.addControlBox();
                     }
                     this.get('controlbox').save({connected:true});
                 },