Index: wp-includes/load.php
===================================================================
--- wp-includes/load.php	(revision 21685)
+++ wp-includes/load.php	(working copy)
@@ -583,8 +583,11 @@
  * @return bool True if inside WordPress administration pages.
  */
 function is_admin() {
-	if ( defined( 'WP_ADMIN' ) )
+	if ( isset( $GLOBALS['current_screen'] ) )
+		return $GLOBALS['current_screen']->in_admin();
+	elseif ( defined( 'WP_ADMIN' ) )
 		return WP_ADMIN;
+
 	return false;
 }
 
@@ -599,8 +602,11 @@
  * @return bool True if inside WordPress network administration pages.
  */
 function is_blog_admin() {
-	if ( defined( 'WP_BLOG_ADMIN' ) )
+	if ( isset( $GLOBALS['current_screen'] ) )
+		return $GLOBALS['current_screen']->in_admin( 'blog' );
+	elseif ( defined( 'WP_BLOG_ADMIN' ) )
 		return WP_BLOG_ADMIN;
+
 	return false;
 }
 
@@ -615,8 +621,11 @@
  * @return bool True if inside WordPress network administration pages.
  */
 function is_network_admin() {
-	if ( defined( 'WP_NETWORK_ADMIN' ) )
+	if ( isset( $GLOBALS['current_screen'] ) )
+		return $GLOBALS['current_screen']->in_admin( 'network' );
+	elseif ( defined( 'WP_NETWORK_ADMIN' ) )
 		return WP_NETWORK_ADMIN;
+
 	return false;
 }
 
@@ -631,8 +640,11 @@
  * @return bool True if inside WordPress user administration pages.
  */
 function is_user_admin() {
-	if ( defined( 'WP_USER_ADMIN' ) )
+	if ( isset( $GLOBALS['current_screen'] ) )
+		return $GLOBALS['current_screen']->in_admin( 'user' );
+	elseif ( defined( 'WP_USER_ADMIN' ) )
 		return WP_USER_ADMIN;
+
 	return false;
 }
 
Index: wp-admin/includes/screen.php
===================================================================
--- wp-admin/includes/screen.php	(revision 21685)
+++ wp-admin/includes/screen.php	(working copy)
@@ -244,9 +244,21 @@
 	public $id;
 
 	/**
+	 * Which admin the screen is in. network | user | blog | false
+	 *
+	 * @since 3.5.0
+	 * @var string
+	 * @access protected
+	 */
+	protected $in_admin;
+
+	/**
 	 * Whether the screen is in the network admin.
 	 *
+	 * Deprecated. Use in_admin() instead.
+	 *
 	 * @since 3.3.0
+	 * @deprecated 3.5.0
 	 * @var bool
 	 * @access public
 	 */
@@ -255,7 +267,10 @@
 	/**
 	 * Whether the screen is in the user admin.
 	 *
+	 * Deprecated. Use in_admin() instead.
+	 *
 	 * @since 3.3.0
+	 * @deprecated 3.5.0
 	 * @var bool
 	 * @access public
 	 */
@@ -377,7 +392,7 @@
 			return $hook_name;
 
 		$post_type = $taxonomy = null;
-		$is_network = $is_user = false;
+		$in_admin = false;
 		$action = '';
 
 		if ( $hook_name )
@@ -402,10 +417,10 @@
 		if ( ! $post_type && $hook_name ) {
 			if ( '-network' == substr( $id, -8 ) ) {
 				$id = substr( $id, 0, -8 );
-				$is_network = true;
+				$in_admin = 'network';
 			} elseif ( '-user' == substr( $id, -5 ) ) {
 				$id = substr( $id, 0, -5 );
-				$is_user = true;
+				$in_admin = 'user';
 			}
 
 			$id = sanitize_key( $id );
@@ -419,13 +434,22 @@
 					$post_type = $maybe;
 				}
  			}
+
+			if ( ! $in_admin )
+				$in_admin = 'blog';
 		} else {
-			$is_network = is_network_admin();
-			$is_user = is_user_admin();
+			if ( defined( 'WP_NETWORK_ADMIN' ) && WP_NETWORK_ADMIN )
+				$in_admin = 'network';
+			elseif ( defined( 'WP_USER_ADMIN' ) && WP_USER_ADMIN )
+				$in_admin = 'user';
+			else
+				$in_admin = 'blog';
 		}
 
 		if ( 'index' == $id )
 			$id = 'dashboard';
+		elseif ( 'front' == $id )
+			$in_admin = false;
 
 		$base = $id;
 
@@ -476,10 +500,10 @@
 				break;
 		}
 
-		if ( $is_network ) {
+		if ( 'network' == $in_admin ) {
 			$id   .= '-network';
 			$base .= '-network';
-		} elseif ( $is_user ) {
+		} elseif ( 'user' == $in_admin ) {
 			$id   .= '-user';
 			$base .= '-user';
  		}
@@ -497,8 +521,9 @@
 		$screen->action     = $action;
 		$screen->post_type  = (string) $post_type;
 		$screen->taxonomy   = (string) $taxonomy;
-		$screen->is_user    = $is_user;
-		$screen->is_network = $is_network;
+		$screen->is_user    = ( 'user' == $in_admin );
+		$screen->is_network = ( 'network' == $in_admin );
+		$screen->in_admin   = $in_admin;
 
 		self::$_registry[ $id ] = $screen;
 
@@ -528,6 +553,23 @@
 	private function __construct() {}
 
 	/**
+	 * Indicates whether the screen is in a particular admin
+	 *
+	 * @since 3.5.0
+	 *
+	 * @param string $admin The admin to check against (network | user | blog).
+	 * If empty any of the three admins will result in true.
+	 * @return boolean True if the screen is in the indicated admin, false otherwise.
+	 *
+	 */
+	public function in_admin( $admin = null ) {
+		if ( empty( $admin ) )
+			return (bool) $this->in_admin;
+
+		return ( $admin == $this->in_admin );
+	}
+
+	/**
 	 * Sets the old string-based contextual help for the screen.
 	 *
 	 * For backwards compatibility.