   if (!this._addons) {
        this._addons = [];
      }
      var target = event.target;
      if (this._addons.indexOf(target) === -1) {
        this._addons.push(target);
        if (this.isAttached) {
          this._handleValue(this._inputElement);
        }
      }
    },

    _onFocus: function() {
      this._setFocused(true);
    },

    _onBlur: function() {
      this._setFocused(false);
      this._handleValueAndAutoValidate(this._inputElement);
    },

    _onInput: function(event) {
      th