title: How can i make custom Polymer element hidden?
body: <p>For experiments I use the custom element <strong>tute-stopwatch</strong> from <a href="https://www.dartlang.org/docs/tutorials/polymer-intro/" rel="nofollow">https://www.dartlang.org/docs/tutorials/polymer-intro/</a></p>
  
  <p>When I set the attribute '.hidden = true' for buttons, these buttons hide successfully, but the element <code>tute-stopwatch</code> doesn't.</p>
  
  <pre class="lang-dart prettyprint-override"><code>  void addChild(Event e, var detail, Node target) {
      ..
      stopButton.hidden = true;
      startButton.hidden = true;
      resetButton.hidden = true;
  
      this.hidden = true; 
  }
  </code></pre>
  
  <p>When i use subtemplate in tute_stop_watch.html:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;template if="{{ visible }}" id="innerTemplate"&gt;
  </code></pre>
  
  <p>and in tute_stop_watch.dart:</p>
  
  <pre class="lang-dart prettyprint-override"><code>  void enteredView() {
      super.enteredView();
      startButton = $['startButton']; // $['startButton'] == null
      innerTemplate =$['innerTemplate'] // find correct, but innerTemplate.childNodes == []
  </code></pre>
  
  <p>I try make element with all abilities tute-stopwatch visible on demand.</p>