title: Perform event in the paper-button inside a dom-repeat template
body: <p>I have the following element:</p>
  
  <pre><code>&lt;dom-module id="my-blogentry"&gt;
  &lt;template&gt;
      &lt;style&gt;
          :host {
              display: block;
          }
          .div-general{
        &lt;/style&gt;
      &lt;div class="div-general"&gt;
          &lt;template is="dom-repeat" items="{{entries}}"&gt;
              &lt;paper-material elevation="1" animated="true" class="paper-material-presentation"&gt;
                  &lt;div class="div-date-left"&gt;
                      &lt;span&gt;{{item.date}}&lt;/span&gt;
                  &lt;/div&gt;
                  &lt;div&gt;
                      &lt;iron-image src$="../../images/{{item.image}}" style="width:128px; height:128px;" sizing="cover"&gt;&lt;/iron-image&gt;
                      {{item.resume}} 
                      &lt;paper-button id="bt_readmore" on-tap="toggle"&gt;Read More&lt;/paper-button&gt;
                      &lt;iron-collapse id="collapse"&gt;
                        &lt;div&gt;{{item.content}}&lt;/div&gt;
                      &lt;/iron-collapse&gt;
                  &lt;/div&gt;
              &lt;/paper-material&gt;
          &lt;/template&gt;
      &lt;/div&gt;
  &lt;/template&gt;
  &lt;script&gt;
      Polymer({
          is: 'my-blogentry',
  
          ready: function() {
              this.entries = [
                  {id: '1', title: ‘xxx.', date: 'Tuesday, March 8, 2016', image:'im-blogdefault.png', resume:’xxx’,content:’xxxx’}
              ];
            },
  
          toggle: function () {
              this.$$('#collapse').toggle();
          }
      });
  
  &lt;/script&gt;
  </code></pre>
  
  <p>If you could check on the element code I have an <code>iron-collapse</code> element inside the <code>&lt;template dom-repeat&gt;</code> and a button. My proposal is the user could tap on the button and toggle the button to open the collapse element.  </p>
  
  <p>The problem is that the code that I have work fine with open the first item, but when I have more items on the list and I press the second item button the first and second collapse  is open too.  </p>
  
  <p>I was searching other posts here in the forum and I found this:<br>
  <a href="https://www.polymer-project.org/1.0/docs/devguide/templates.html#handling-events" rel="nofollow">Documentation</a>
  This example modify the items in the model but no the DOM that it is what I need (toggle my iron-collapse element).</p>
  
  <p>I'll appreciate any help on that.</p>