title: WCF Tracing switchvalue is Off yet there is still a trace output being generated
body: <p>After having turned on WCF Tracing to assist with finding a problem, I now wish to turn off tracing.  So I have changed my config file to this...</p>
  
  <pre><code>&lt;system.diagnostics&gt;
          &lt;sources&gt;
              &lt;source name="System.ServiceModel" switchValue="Off" &gt;
                  &lt;!-- Information,ActivityTracing--&gt;
                  &lt;listeners&gt;
                      &lt;add name="xmlTraceListener" /&gt;
                  &lt;/listeners&gt;
              &lt;/source&gt;
              &lt;source name="System.ServiceModel.MessageLogging" switchValue="Off" &gt;
                  &lt;listeners&gt;
                      &lt;add name="xmlTraceListener" /&gt;
                  &lt;/listeners&gt;
              &lt;/source&gt;
          &lt;/sources&gt;
          &lt;sharedListeners&gt;
              &lt;add name="xmlTraceListener" 
                   type="System.Diagnostics.XmlWriterTraceListener" 
                   initializeData="C:\WCFLogs\DataPortalTrace.svclog" /&gt;
          &lt;/sharedListeners&gt;
          &lt;trace autoflush="true" /&gt;
      &lt;/system.diagnostics&gt;
  </code></pre>
  
  <p>Yet there is still trace output being send to the indicated output file.  Why is that?  What am I missing?</p>