title: overflow:auto doesn't work, does not show the scroll bar
body: <p>I need to put a vertical scrollbar on each md-content (content-left &amp; content-right). I've been trying to figure this out for several hours, but it isn't working.</p>
  
  <p>This is my example code: <a href="http://codepen.io/anon/pen/zvvodN" rel="noreferrer">http://codepen.io/anon/pen/zvvodN</a></p>
  
  <p>html:  </p>
  
  <pre><code>  &lt;div ng-controller="AppCtrl" class="listdemoBasicUsage" ng-app="MyApp" &gt;
        &lt;div layout="row" class="main"&gt;
        &lt;div flex="50" class="left"&gt;  
          &lt;md-content class="content-left"&gt;
          &lt;md-list&gt;
            &lt;md-subheader class="md-no-sticky"&gt;3 line item&lt;/md-subheader&gt;
            &lt;md-list-item class="md-3-line" ng-repeat="item in todos"&gt;
              &lt;img ng-src="{{item.face}}?{{$index}}" class="md-avatar" alt="{{item.who}}"&gt;
              &lt;div class="md-list-item-text" layout="column"&gt;
                &lt;h3&gt;{{ item.who }}&lt;/h3&gt;
                &lt;h4&gt;{{ item.what }}&lt;/h4&gt;
                &lt;p&gt;{{ item.notes }}&lt;/p&gt;
              &lt;/div&gt;
            &lt;/md-list-item&gt;
          &lt;/md-list&gt;
        &lt;/md-content&gt;
        &lt;/div&gt;
  
  
         &lt;div flex class="right"&gt;  
          &lt;md-content class"content-right"&gt;
          &lt;md-list&gt;
            &lt;md-subheader class="md-no-sticky"&gt;3 line item&lt;/md-subheader&gt;
            &lt;md-list-item class="md-3-line" ng-repeat="item in todos"&gt;
              &lt;img ng-src="{{item.face}}?{{$index}}" class="md-avatar" alt="{{item.who}}"&gt;
              &lt;div class="md-list-item-text" layout="column"&gt;
                &lt;h3&gt;{{ item.who }}&lt;/h3&gt;
                &lt;h4&gt;{{ item.what }}&lt;/h4&gt;
                &lt;p&gt;{{ item.notes }}&lt;/p&gt;
              &lt;/div&gt;
            &lt;/md-list-item&gt;
          &lt;/md-list&gt;
        &lt;/md-content&gt;
        &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>css:</p>
  
  <pre><code>body{
    overflow:hidden;}
  .main{
    border: 2px solid red;}
  .left{
    border: 2px solid green;}
  .content-left{
    overflow:auto;}
  .right{
    border: 2px solid blue;}
  .content-right{
    overflow: auto;}
  </code></pre>
  
  <p>Thank you for your help.</p>