Save and return to edit new or update node.

gistfile1.php

<?php

/**
 * @file
 * Replace the submit button to node creation forms that
 * allows the content author to return to edit the node
 */

/**
 * Implementation of hook_form_alter().
 */
 
 /**
 * Alter content type settings to add "Save node and return to edit" checkbox
 */
function saveandreturn_form_node_type_form_alter(&$form, &$form_state) {
  if (isset($form['identity']['type'])) {
    $form['submission']['saveandreturn'] = array(
      '#type' => 'checkbox',
      '#title' => t('Save and Edit'),
      '#default_value' => variable_get('saveandreturn_'. $form['#node_type']->type, FALSE),
      '#description' => t('Enable this checkbox if you want to provide a "Save node and return to edit"')
    );
  }
}

function saveandreturn_form_alter(&$form, $form_state, $form_id) {
	/* Remove all preview nodes buttom */
	if(strpos($form_id, '_node_form')){
		unset($form['buttons']['preview']);
	}
		
	if(strpos($form_id, '_node_form') && !isset($form['nid']['#value'])) {
    
	if (variable_get('saveandreturn_'. $form['type']['#value'], FALSE)) {
	
      $form['buttons']['submit'] = array(
        '#type' => 'submit',
        '#value' => t('Save and Edit'),
        '#weight' => -41,
        '#submit' => array('node_form_submit', 'saveandreturn_node_form_submit'),
      );
  	
    }
  }
}

function saveandreturn_node_form_submit($form, &$form_state) {
  //$link = l(t('Visit your new post.'), 'node/'. $form_state['nid']);
  drupal_set_message('Your post was successfully saved!');
  $form_state['redirect'] = NULL;
  unset($_REQUEST['destination'], $_REQUEST['edit']['destination']);
}