private void previewButton_Click(object sender, RoutedEventArgs e)
        {
            string previewSource = HtmlGenerator.GeneratePreviewHtml(page);

            var previewWindow = new PreviewWindow();

            previewWindow.HtmlSource = previewSource;
            previewWindow.Owner      = this;
            previewWindow.ShowModal();
        }
        private void copyHtmlButton_Click(object sender, RoutedEventArgs e)
        {
            string source = HtmlGenerator.GenerateHtml(page);

            Clipboard.SetText(source, TextDataFormat.UnicodeText);
        }