title: Firefox extension: gBrowser is not defined
body: <p>This is a Firefox extension and everything is working pretty good.</p>
  
  <p>BUT...
  I keep getting the irritating "gBrowser is not defined" error in the console because of this line:</p>
  
  <pre><code>gBrowser.selectedTab = gBrowser.addTab("chrome://ire_TPB/content/options.html");
  </code></pre>
  
  <p>What I am trying to do of course is open a new tab and load that local html page.</p>
  
  <p>What am I doing wrong?</p>
  
  <p>Thanks!</p>
  
  <p>Win 7 ult<br>
  FF 7.0</p>