I am baffled by the following.
I have this code in a block:
<div id="headcontact">
<ul><li><em class="mini-ico-envelope"></em><a href="mailto:
mail@mail.org">
mail@mail.org</a></li><li><em class="mini-ico-user"></em> (999) 463 1234</li>
</ul>
</div>
I close the block after editing and the em tag can be seen in firebug and it works as intended. I am using css transitions and glyphicons.