title: Excel autocomplete formula
body: <p>When I'm typing a long formula command in excel, like <code>sumproduct</code>, I can type '=s', and get a listbox with possibilities.<br>
  I want to direct with my arrow keys to the right formula and click on enter to autocomplete it to <code>sumproduct</code>.</p>
  
  <p>I can't find out how to do this. Who knows?</p>