onOkay = function (event) {
    CustomDialog.hide();
    options.onOkay && options.onOkay();
    event && event.stopPropagation();
  }
Shows the dialog.
Allowed options:
 - showOkay: Whether to show the OK button.
 - showCancel: Whether to show the Cancel button.
 - showInput: Whether to show the text input field.
 - onOkay: Callback to handle the okay button.
 - onCancel: Callback to handle the cancel button and backdrop clicks.