1. Visit Tickets > Settings > File Upload
2. Ensure "Enable File Upload", "Enable drag-n-drop uploader for ticket form", and "Check this to allow users to delete attachments" are checked, and save the settings.
3. As a ticket submitter, open the form to submit a ticket. Upload an attachment.
4. Remove the attachment, and intercept the request. Replace the file name with `../../../../wp-config.php`.
5. Reload the page to see that the `wp-config.php` file has been deleted.