我在mandrill模板中有以下html。

<!--[if mso]>
<v:rect class="btn-vml" href="https://my.petplan.co.uk?utm_source=e-docs&utm_medium=email&utm_campaign=e-docs-nb" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:w="urn:schemas-microsoft-com:office:word" style="height:40px; v-text-anchor:middle; width:240px;" strokecolor="#f47721" fillcolor="#f47721">
<w:anchorlock/>
               <center style="color:#ffffff;font-family: Tahoma,sans-serif; font-size:15px;">Register for My Petplan</center>
       </v:rect>
<![endif]-->
<a class="btn" href="https://my.petplan.co.uk?utm_source=e-docs&utm_medium=email&utm_campaign=e-docs-nb" title="Register for My Petplan" target="_blank" style="background-color:#f47721; color:#ffffff; display:inline-block; font-family:'American Typewriter',Tahoma,sans-serif; font-size:15px; line-height:40px; text-align:center; text-decoration:none; width:220px; -webkit-text-size-adjust:none;outline:0; mso-hide:all;">Register for My Petplan</a>

有人知道为什么将点击标记应用于锚标记中的href而不是v：rect标记的href中吗？