title: ExtJS 3 keep combobox always expanded
body: <p>I am currently working on an old project with <code>ExtJS 3.0.0</code>, without possibility to upgrade version. My goal is to make a combobox always open, so that the user does not have to click the arrow in order to view the options.</p>
  <p>I found out that by overriding the <code>collapse</code> event listener, I can prevent the combobox from closing once it is expanded</p>
  <pre><code>   myCombo.addListener(
          'collapse',
          function() { 
              this.expand();
           }
      );
  </code></pre>
  <p>However I cannot find any way to expand it programmatically once the panel is rendered. I experimented with <code>specialkey</code> and <code>keypress</code> events, but I do not know how they should be triggered.</p>
  <p>Any ideas on how I could achieve this?</p>