diff --git a/classes/context/Context.class.php b/classes/context/Context.class.php
index 02e349330..ae5403692 100644
--- a/classes/context/Context.class.php
+++ b/classes/context/Context.class.php
@@ -358,6 +358,7 @@ class Context
 		}
 		else
 		{
+			$this->isSessionStarted = FALSE;
 			$_SESSION = array();
 		}
 
@@ -475,6 +476,26 @@ class Context
 		session_write_close();
 	}
 
+	/**
+	 * set Cache-Control header
+	 *
+	 * @return void
+	 */
+	function setCacheControl($public = 'public', $nocache = false)
+	{
+		is_a($this, 'Context') ? $self = $this : $self = self::getInstance();
+
+		$public = !empty($public) ? $public.', ' : '';
+		header("Cache-Control: ".$public."must-revalidate, post-check=0, pre-check=0");
+		if ($nocache)
+		{
+			header("Cache-Control: no-store, no-cache, must-revalidate", false);
+			header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
+			header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
+			header("Pragma: no-cache");
+		}
+	}
+
 	/**
 	 * Load the database information
 	 *
diff --git a/classes/display/DisplayHandler.class.php b/classes/display/DisplayHandler.class.php
index ca160a57c..8c89f138d 100644
--- a/classes/display/DisplayHandler.class.php
+++ b/classes/display/DisplayHandler.class.php
@@ -324,11 +324,6 @@ class DisplayHandler extends Handler
 	function _printXMLHeader()
 	{
 		header("Content-Type: text/xml; charset=UTF-8");
-		header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
-		header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
-		header("Cache-Control: no-store, no-cache, must-revalidate");
-		header("Cache-Control: post-check=0, pre-check=0", false);
-		header("Pragma: no-cache");
 	}
 
 	/**
@@ -338,11 +333,6 @@ class DisplayHandler extends Handler
 	function _printHTMLHeader()
 	{
 		header("Content-Type: text/html; charset=UTF-8");
-		header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
-		header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
-		header("Cache-Control: no-store, no-cache, must-revalidate");
-		header("Cache-Control: post-check=0, pre-check=0", false);
-		header("Pragma: no-cache");
 	}
 
 	/**
@@ -352,11 +342,6 @@ class DisplayHandler extends Handler
 	function _printJSONHeader()
 	{
 		header("Content-Type: text/html; charset=UTF-8");
-		header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
-		header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
-		header("Cache-Control: no-store, no-cache, must-revalidate");
-		header("Cache-Control: post-check=0, pre-check=0", false);
-		header("Pragma: no-cache");
 	}
 
 	/**
diff --git a/classes/mobile/Mobile.class.php b/classes/mobile/Mobile.class.php
index c38ffcf21..db2ac82aa 100644
--- a/classes/mobile/Mobile.class.php
+++ b/classes/mobile/Mobile.class.php
@@ -123,13 +123,13 @@ class Mobile
 					setcookie("mobile", 'true', 0, $xe_web_path);
 				}
 			}
-			elseif($_COOKIE['mobile'] != 'false')
+			elseif(isset($_COOKIE['mobile']) && $_COOKIE['mobile'] != 'false')
 			{
 				$_COOKIE['mobile'] = 'false';
 				setcookie("mobile", 'false', 0, $xe_web_path);
 			}
 
-			if($_COOKIE['user-agent'] != md5($_SERVER['HTTP_USER_AGENT']))
+			if(isset($_COOKIE['mobile']) && $_COOKIE['user-agent'] != md5($_SERVER['HTTP_USER_AGENT']))
 			{
 				setcookie("user-agent", md5($_SERVER['HTTP_USER_AGENT']), 0, $xe_web_path);
 			}