field_group: the save button is now in the wrong place
You can change the weight of the Save / preview buttons, and place them at the bottom with form alter.

Weight is used to sort the list of form elements before being output; lower numbers appear before higher numbers.

function YOUR_MODULE_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  // Only change actions container (submit, preview, cancel buttons) weight
  // on node edit forms.
  if (!empty($form['#node_edit_form']) &amp;&amp; $form['#node_edit_form'] == TRUE) {
    $form['actions']['#weight'] = 100; 
  }
}