Why is page tpl not getting detected
This is the snippet I wrote for  region--login.tpl.php try this once. Hope it meets your requirements.
in template.php

 &lt;?php
 function yourthemeName_theme() {
   $items = array();
  // create custom user-login.tpl.php
  $items['user_login'] = array(
  'render element' =&gt; 'form',
  'path' =&gt; drupal_get_path('theme', 'yourthemeName') . '/templates',
  'template' =&gt; 'region--login',
   'preprocess functions' =&gt; array(
   'yourthemeName_preprocess_user_login'
   ),
   );
   return $items;
  }
  ?&gt;