Hi, I'm doing some custom validation on server side by attaching an event listener to FormsSubmitting event.

[ModuleDependency(typeof(EPiServer.Web.InitializationModule))]
    public class FormInitializationModule : IInitializableModule
    {
        public void Initialize(InitializationEngine context)
        {
            FormsEvents formsEvents = ServiceLocator.Current.GetInstance<FormsEvents>();
            formsEvents.FormsSubmitting += OnFormSubmitting;
        }

        private void OnFormSubmitting(object sender, FormsEventArgs e)
        {
            FormsSubmittingEventArgs submitArgs = e as FormsSubmittingEventArgs;
            IEpiFormCustomValidator formValidator = ServiceLocator.Current.GetInstance<IEpiFormCustomValidator>();
            EpiFormCustomValidationResult validationResult = formValidator.Validate(submitArgs.SubmissionData.Data);
            if (!validationResult.IsValid)
            {
                submitArgs.CancelAction = true;
                submitArgs.CancelReason = validationResult.Errors.Select(x => x.Value).FirstOrDefault(); // return first error message
            }
        }

        public void Uninitialize(InitializationEngine context)
        {
            FormsEvents formsEvents = ServiceLocator.Current.GetInstance<FormsEvents>();
            formsEvents.FormsSubmitting -= OnFormSubmitting;
        }
    }

The form is cancelled as expected but the message is quite odd.

Is there any way to replace the whole responsed message (the part inside green circle) instead of just the CancelReason part?