title: How to show/hide a MarkerCluster in google maps v3?
body: <p>I need to have different markers for different <code>mapType</code>s, and I'm pushing them to a <a href="http://code.google.com/p/google-maps-utility-library-v3/wiki/Libraries#MarkerClusterer" rel="noreferrer">MarkerClusterer</a>.</p>
  
  <p>I "hide" the markers with:</p>
  
  <pre><code>cluster.set("map", null);
  cluster.resetViewport();
  cluster.redraw();
  </code></pre>
  
  <p>And "show" them with:</p>
  
  <pre><code>cluster.set("map", MAP);
  cluster.resetViewport();
  cluster.redraw();
  </code></pre>
  
  <p>The problem is that MarkerClusterer seems to not like <code>set("map", null)</code>; it throws the error <code>TypeError: Object #&lt;a MarkerClusterer&gt; has no method 'remove'</code>. How can I show/hide them the proper way?</p>