diff -crB mag1500/app/code/core/Mage/Admin/Model/Observer.php mag1500-PATCH/app/code/core/Mage/Admin/Model/Observer.php
*** mag1500/app/code/core/Mage/Admin/Model/Observer.php	2011-02-03 13:34:05.000000000 +0000
--- mag1500-PATCH/app/code/core/Mage/Admin/Model/Observer.php	2015-02-11 15:37:08.000000000 +0000
***************
*** 37,42 ****
--- 37,45 ----
      {
          $session  = Mage::getSingleton('admin/session');
          /* @var $session Mage_Admin_Model_Session */
+         /**
+          * @var $request Mage_Core_Controller_Request_Http
+          */
          $request = Mage::app()->getRequest();
          $user = $session->getUser();
  
***************
*** 55,61 ****
                      $user = $session->login($username, $password, $request);
                      $request->setPost('login', null);
                  }
!                 if (!$request->getParam('forwarded')) {
                      if ($request->getParam('isIframe')) {
                          $request->setParam('forwarded', true)
                              ->setControllerName('index')
--- 58,65 ----
                      $user = $session->login($username, $password, $request);
                      $request->setPost('login', null);
                  }
!                 if (!$request->getInternallyForwarded()) {
!                     $request->setInternallyForwarded();
                      if ($request->getParam('isIframe')) {
                          $request->setParam('forwarded', true)
                              ->setControllerName('index')
diff -crB mag1500/app/code/core/Mage/Core/Controller/Request/Http.php mag1500-PATCH/app/code/core/Mage/Core/Controller/Request/Http.php
*** mag1500/app/code/core/Mage/Core/Controller/Request/Http.php	2011-02-03 13:34:01.000000000 +0000
--- mag1500-PATCH/app/code/core/Mage/Core/Controller/Request/Http.php	2015-02-11 15:35:36.000000000 +0000
***************
*** 72,77 ****
--- 72,84 ----
       * @var array
       */
      protected $_beforeForwardInfo = array();
+     
+     /**
+      * Flag for recognizing if request internally forwarded
+      *
+      * @var bool
+      */
+     protected $_internallyForwarded = false;
  
      /**
       * Returns ORIGINAL_PATH_INFO.
***************
*** 528,531 ****
--- 535,560 ----
          }
          return false;
      }
+     
+     /**
+      * Define that request was forwarded internally
+      *
+      * @param boolean $flag
+      * @return Mage_Core_Controller_Request_Http
+      */
+     public function setInternallyForwarded($flag = true)
+     {
+     	$this->_internallyForwarded = (bool)$flag;
+     	return $this;
+     }
+     
+     /**
+      * Checks if request was forwarded internally
+      *
+      * @return bool
+      */
+     public function getInternallyForwarded()
+     {
+     	return $this->_internallyForwarded;
+     }
  }