Code:
on 1:dialog:name:init:0: {
  var %rand = $rand(<ID>,$did($dname,<ID>).lines)
  did -c name ID %rand
}


That randomizes a line number in your combo box and checks it.

If you don't want it to randomize it try.

Code:
on 1:dialog:name:init:0: {
  did -c name ID 1
}


That would check the first line in the combo box, hope this helps. smile