cms.form.beforeStep

Triggered in Cms\Behaviors\WizardComponent.

Fires before a form step is saved, throw an exception to reject it.

Example usage:

Event::listen('cms.form.beforeStep', function ($component, $model, $tag) {
    if ($tag === 'step1' && !CaptchaService::verify()) {
        throw new ValidationException(['captcha' => 'Please complete the captcha.']);
    }
});