title: How to destroy all instances of a object with ExtJS?
body: <p>I created 2 panels like that with the framework ExtJS (i know it's not the best way):</p>
  
  <pre><code>var panel = Ext.create("Ext.panel.Panel", {
                  title: "first panel",
                  width: 400,
                  height: 250,
                  renderTo: Ext.getBody(),
                  html: "test 1"
              });
  
  panel = Ext.create("Ext.panel.Panel", {
                  title: "second panel",
                  width: 400,
                  height: 250,
                  renderTo: Ext.getBody(),
                  html: "test 2"
              });
  </code></pre>
  
  <p>Now I have 2 panels in my browser. And now if I do this:</p>
  
  <pre><code>panel.destroy();
  </code></pre>
  
  <p>It destroys only the last one.
  So my question is : How can I destroy the first panel? Is there a method which contains all the panels in the browser? Do I store the IDs' panels each time in order to destroy them later?...</p>