Own submit handler in panels_edit_display?

Seems like it is impossible to hand over a custom submit handler to panels_edit_display()...
This would mean that the code

  if ($submit) {
    // The caller wants their own submit.
    $form['#submit'] = array($submit => array());
  }

in display_edit.inc (line 160ff.) was nonsense, or do I miss something?
Also it looks pretty awkward - doesn't it need to be: $form['#submit'] = array($submit)?

If I'm right, we can either remove those lines or add an optional $submit = NULL argument to the definition. I'd vote for the former then, to keep it simple. We might want to introduce that in a later API version.