domain_form_alter and CCK conflict

For some reason, the implementation of domain_form_alter causes an extra body field to be displayed on CCK field management forms. It also prevents CCK from processing the form correctly.

The following fix corrects the issue, but I'd still like to understand the root cause.

function domain_form_alter($form_id, &$form) {
  if ($form['#id'] == 'node-form' && !$form['#node']->cck_dummy_node_form) {

CCK sets teh 'cck_dummy_node_form' property for just this reason.