title: div disappearing in IE7
body: <p>I have a problem with a div in IE7, it's disappearing and I don't understand why.
  I already tried to add zoom:1 and overflow: hidden as someone suggested but it is not working. </p>
  
  <p>The div is inside an unordered list (floated left) as the last element, floated right.</p>
  
  <p>This is the HTML</p>
  
  <pre><code>&lt;div id="top_menu"&gt;
      &lt;ul id="dropmenu"&gt;
          &lt;li&gt;menu item1&lt;/li&gt;
          &lt;li&gt;menu item2&lt;/li&gt;
          ...
       &lt;/ul&gt;
      &lt;div class="lang"&gt;content&lt;/div&gt;
  &lt;/div&gt;&lt;!-- end top menu --&gt;
  </code></pre>
  
  <p>This is the CSS</p>
  
  <pre><code>  #top_menu                     {width:900px;font-size:13px; }
      #top_menu ul#dropmenu           {width:630px; height:28px; margin:0px; padding:0px; list-style:none; float:left; }
      #top_menu ul#dropmenu li        {float:left;display:block;}
      .clearfix                       {display: inline-block;}  /* for IE/Mac */
  
      #top_menu .lang { width: 120px; color:#fff; margin:4px 10px 0 0; float: right; }
      #top_menu .lang a{ color:#ff8601; }
      #top_menu .lang a:hover{ color:#fff; }
  </code></pre>
  
  <p>Thanks for your help</p>
  
  <p>EDIT: I included the html and removed url to avoid client complaints.</p>