column-list works fine fieldset, just not the word-wrap.
<fieldset>
<ul>
<li><a href="#">foo</a> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa</li>
<li>bbbbbb</li>
<li>ccccccc</li>
<li>aaaaaaaa</li>
<li><a href="#">foo</a>aaaaaaaa</li>
<li>aaaaaaaa</li>
<li>aaaaaaaa</li>
</ul>
</fieldset>
ul {
-webkit-column-count: 3;
-moz-column-count: 3;
column-count: 3;
}
ul li{
word-wrap: break-word;
}
Test: http://jsfiddle.net/jbe07sbs/1/
Tested in Chrome 39.0.2171.71 m
demo - http://jsfiddle.net/jbe07sbs/2/