Transactional Email Preview Showing HTML code in Magento 1.6.2.0

This issue exists in Magento version 1.6.2.0. To fix the issue follow below steps.

1. Copy app/code/core/Mage/Adminhtml/Block/System/Email/Template/preview.php file to app/code/local/Mage/Adminhtml/Block/System/Email/Template/preview.php
2. Comment the following lines of code (Starts at line number 47) in protected function _toHtml() method

      $template->setTemplateText(
            $this->escapeHtml($template->getTemplateText())
        );