We are using EPiServer CMS7 and successfully sending out emails.  On the Sent Mailings page, it shows several links have been clicked and on the MessageStatistics page and download via the 'Export clicks', it lists several links.  However, when clicking on 'Show/Hide Link Statistics', each link is shown as '0 clicks'.

Is this a bug in EPiServerMail or is it something we need to do to our email templates or EPiServerMail configuration for this overlay to display the correct number of clicks?