title: Fast replacement for JComboBox / BasicComboBoxUI?
body: <p>I've got a <code>JComboBox</code> that potentially can have thousands of items. They're sorted, and there's find-as-you-type, so in principle it's not completely unusable.</p>
  
  <p>In practice, it's pretty unusable with just a couple of hundred items. I managed to improve the initial display performance using <code>setPrototypeDisplayValue()</code>, but <code>BasicListUI</code> still insists on configuring the list cell renderer for every item in the box (see <code>BasicListUI.updateLayoutState()</code>).</p>
  
  <p>This, or something like it, is apparently a <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4762915" rel="nofollow noreferrer">known issue</a> to Sun; it has been for going on eight years now, so I'm not holding my breath.</p>
  
  <p>Short of implementing my own UI, has anyone got a workaround?</p>