title: How to show/hide ExtJS.Toolbar button programmatically
body: <p>I am attempting to show/hide an ExtJS Toolbar button programmatically. I have tried to access the button directly, by ID using:</p>
  
  <pre><code>var btn = Ext.get('buttonID'); // I've also tried Ext.query('buttonID')
  btn.show();
  </code></pre>
  
  <p>However, this does not cause the button to be shown. The toolbar button is defined with the ID with which I am attempting to execute the <code>show()</code> method.</p>
  
  <p>Is there a different way for me to access the button, directly?  Or, is there a different way to show it (adding/removing CSS attributes, etc.)?</p>
  
  <p>Thank you in advance.</p>