[Xenon]

you can also make new sortoptions to that pulldown:

edit template forumdisplay_threadslist

find the lines
<select name="sortfield">
<option value="title" $sort[title]>thread title</option>

and add this option for example
<option value="threadid" $sort[threadid]>thread startdate</option>

then in forumdisplay.php
find this:

PHP Code:

switch ($sortfield) {
  case 'title':
  case 'lastpost':
  case 'replycount':
  case 'views':
  case 'postusername':
  case 'voteavg':
    break; 


and before the break; add case 'threadid':