title: issues with md-virtual-repeat
body: <p>We are having some IE11 performance issues on an app that's using Angular Material.  I looked into it and apparently this is well known, and started to look at solutions.  One of which was replacing large <code>ng-repeat</code> lists with a <code>md-virtual-repeat</code> directive.  I've tried this and have mixed results.  It boils down to a few issues:</p>
  
  <ol>
  <li>I can't see the items unless I dynamically remove the <code>md-virtual-repeat-container md-orient-vertical</code> class from the <code>md-virtual-repeat-container</code>.</li>
  <li>I have multiple tabs on the page (it is a shopping page sorted by category, with a list under each tab) and the elements are only repeated if I click a tab, then click off, and re-click.</li>
  <li>The height of the div with the class <code>md-virtual-repeat-sizer</code> is absurdly high (~2000px and up to 48000px for larger lists).</li>
  </ol>
  
  <p>At first I thought that it was related to being nested inside of another <code>ng-repeat</code>, but I'm not sure that's the culprit.  Here is a snippet of the relevant code:</p>
  
  <pre><code>&lt;ng-form name="vmProduct.productsForm" novalidate&gt;
  &lt;div ng-repeat="InventoryItemSubCategory in vmProduct.products | filter: ($scope.selectedGroup !== 'All' || '') &amp;&amp; $scope.selectedGroup | filter:$scope.query | groupBy:'InventoryItemSubCategory':'productsByCategory'"&gt;
  &lt;h2&gt;{{InventoryItemSubCategory.InventoryItemSubCategory}}&lt;/h2&gt;
  &lt;md-content ng-cloak=""&gt;
    &lt;md-virtual-repeat-container id="productRepeat"&gt;
      &lt;div md-virtual-repeat="product in InventoryItemSubCategory.items"&gt;
        &lt;md-card class="product-card" md-theme="default" md-theme-watch&gt;
          &lt;md-card-content&gt;
          &lt;/md-card-content&gt;
        &lt;/md-card&gt;
      &lt;/div&gt;
    &lt;/md-virtual-repeat-container&gt;
  &lt;/md-content&gt;
  &lt;/div&gt;
  &lt;/ng-form&gt;
  </code></pre>
  
  <p>My other thought that it was due to using <code>md-card</code> directives instead of <code>div</code> elements but I'm not sure.</p>
  
  <p>Has anyone run into this before?  Any help/direction would be appreciated.</p>
  
  <p>Thanks!</p>