docs: function preferencesDialog_close(saveChanges) {
      saveChanges = (saveChanges == undefined) ? false : saveChanges;
  
      if (mozmill.isWindows) {
        var button = this.getElement({type: "button", subtype: (saveChanges ? "accept" : "cancel")});
        this._controller.click(button);
      } else {
        this._controller.keypress(null, 'w', {accelKey: true});
      }
    }