code: function setParent(p) {
              this.$super(p);
              if (p !== null && p.noSubIfEmpty === true) {
                  this.getSub().setVisible(false);
              }
          }
docs: Override setParent method to catch the moment when the
  item is inserted to a menu
  @param {zebkit.ui.Panel} p a parent
  @method setParent