title: How to use conditions in features in WiX?
body: <p>I am trying to make simple Windows intaller, and I don't know how to deal with this.
  I have two features - feature1 and feature2. I want feature2 to be installed only if the user selected feature1 to be installed. So I tried:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;Feature Id='core' Title='Core'
           Description='ØMQ 1.0.0 core functionality and C++ API' Level='1'&gt;
    &lt;ComponentRef Id='Core_include' /&gt;
    &lt;ComponentRef Id='Core_bin' /&gt;
    &lt;ComponentRef Id='Core_lib' /&gt;
    &lt;ComponentRef Id='Core_zmq' /&gt;
    &lt;ComponentRef Id='cpp_bin' /&gt;
  &lt;/Feature&gt;
  
  &lt;Feature Id='core_perf' Title='core_perf' Description='0MQ core perf' Level='999'&gt;
      &lt;Condition Level="0"&gt;NOT (&amp;amp;core = "3")&lt;/Condition&gt;
          &lt;ComponentRef Id='cpp_perf' /&gt;
  &lt;/Feature&gt;
  </code></pre>
  
  <p>But this doesn't install feature core_perf if the user selects feature core.</p>
  
  <p>How can I fix this?</p>