title: error :id is already registered
body: <p>i have this error in my code</p>
  
  <pre><code>Error: Tried to register widget with id==legend1 but that id is already registered
  </code></pre>
  
  <p>the code for the legend is:</p>
  
  <pre><code>    &lt;div id="legend1"&gt;&lt;/div&gt;
  
      var stackedAreaLegend = new dojox.charting.widget.SelectableLegend({
      chart: chart1
      }, "legend1");   
  
     stackedAreaLegend.refresh(); 
  </code></pre>
  
  <p>how i can solve this error? </p>