Drupal hook menu and node form I have a content type leg and this hook_menu :

$items['leg'] = array(
    'title' =&gt; t('Choose Leg'),
    'page callback' =&gt; 'drupal_get_form',
    'access arguments' =&gt; array('create leg content'),
    'page arguments' =&gt; array('mymodule_leg_select_form'),
    'type' =&gt; MENU_NORMAL_ITEM,
    'weight' =&gt; 0,
);

$items['leg/select'] = array(
    'title' =&gt; t('Choose an existing leg'),
    'page callback' =&gt; 'drupal_get_form',
    'access arguments' =&gt; array('create leg content'),      
    'page arguments' =&gt; array('mymodule_leg_select_form'),
    'type' =&gt; MENU_DEFAULT_LOCAL_TASK,
    'weight' =&gt; 1,
);  

$items['leg/add'] = array(
    'title' =&gt; t('Create a new leg'),
    'page callback' =&gt; 'drupal_get_form',
    'access arguments' =&gt; array('create leg content'),      
    'page arguments' =&gt; array('leg_node_form'),
    'type' =&gt; MENU_LOCAL_TASK,
    'weight' =&gt; 2,
);  
return $items;


Here is the code snippet from mymodule_leg_select_form() which is called as MENU DEFAULT LOCAL TASK :

$form = array();    
$result = db_query('SELECT nid, title FROM {node} WHERE type = :type AND status = :status ORDER BY title', array(':type'=&gt;'leg', ':status'=&gt;1));
$options = array();
foreach($result as $row){
    $options[$row-&gt;nid] = $row-&gt;title;
}
$form['leg'] = array(
    '#type' =&gt; 'select',
    '#title' =&gt; t('Leg'),
    '#options' =&gt; $options,
    '#required' =&gt; TRUE,
);

$form['submit'] = array(
    '#type' =&gt; 'submit', 
    '#value' =&gt; t('Ok'),
    '#weight' =&gt; 1,
);

return $form;


The node form is not rendered correctly as you can see in the screen shot. I have two fields - field_from and field_to. They are not rendered in the form. The menu path "leg/select" which is default local task did work and correctly rendered my custom form.  

The problem only is to integrate node add form in the second tab.
How can I fix this error ?
The problem is not your hook_menu implementation, but your function leg_node_form. That function probably calles node_form, which is in file modules/node/node.pages.inc you have to include that file manually using module_load_include.