Steps to reproduce:

• You have a JsCallback opened by on click as a modal with confirmation:

$button->on('click', null, null, ['confirm' => 'Really delete?'])->atkAjaxec([
                'url' => $jsCallbackDelete
]);

Expected behaviour (as it was until just recently):

• jsCallbackDelete is called
• Modal is closed

Erroneous behaviour now:

• jsCallbackDelete is called
• Modal is not closed, JS error thrown:

Please fix @mvorisek