title: jquery-ui: Dialog not opened at vertical center
body: <p>I have a jquery ui dialog which is defined as this:</p>
  
  <pre><code>$('#processPosition').dialog({
          autoOpen : false,
          open: function ()
          {           
              dialogProps.originalContent = $("#processPosition").html(),
              dialogProps.type = $(this).data('type');
  
              $('#' + dialogProps.type).appendTo($(this));
              $('#rejectPosition').appendTo($(this));
              $("#processPosition .template").removeClass("template");
          },
          show : "blind",
          modal : true,
          resizable : false,
          scrollbar : false
      });
  </code></pre>
  
  <p>This is how i open it:</p>
  
  <pre><code>$('#processOrderPosition').dialog({width: 800})
                            .dialog('option', 'position', 'center')
                            .dialog("open");
  </code></pre>
  
  <p>This is the only css of the template class:</p>
  
  <pre><code>.template
  {
      display: none;
  }
  </code></pre>
  
  <p>Html template <code>div</code>s:</p>
  
  <pre><code>&lt;div id="SAP-flst-Dialog" class="template"&gt;
      &lt;h4&gt;Header&lt;/h4&gt;
      &lt;div class="row"&gt;
          &lt;span&gt;Some text&lt;/span&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;div id="rejectOrderPosition" class="template"&gt;
      &lt;h4&gt;second Header&lt;/h4&gt;
      &lt;span&gt;Some more Text&lt;/span&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I also tried to set the position attribute after opening it, but with no effect. In the dev tools of my browser i can see, that a <code>div</code> is generated by jquery and this div has a wrong value for the css <code>top</code> attribute. The <code>div</code> has the following classes: <code>ui-dialog ui-widget ui-widget-content ui-corner-all ui-front ui-draggable</code></p>
  
  <p>What is causing the wrong top value?</p>