diff --git a/wp-admin/css/wp-admin.css b/wp-admin/css/wp-admin.css
index 9fd22a5a7d..8cb0e3bfc8 100644
--- a/wp-admin/css/wp-admin.css
+++ b/wp-admin/css/wp-admin.css
@@ -7187,7 +7187,7 @@ body.interim-login {
 
 .interim-login #login {
 	padding: 0;
-	margin: 25px auto 20px;
+	margin: 5px auto 20px;
 }
 
 .interim-login.login h1 a {
diff --git a/wp-includes/css/wp-auth-check.css b/wp-includes/css/wp-auth-check.css
index 6a4c56f597..f51017b59f 100644
--- a/wp-includes/css/wp-auth-check.css
+++ b/wp-includes/css/wp-auth-check.css
@@ -24,10 +24,10 @@
 	overflow: hidden;
 	top: 40px;
 	bottom: 20px;
-	max-height: 435px;
+	max-height: 415px;
 	width: 380px;
 	margin: 0 0 0 -190px;
-	padding: 0;
+	padding: 30px 0 0;
 	background-color: #fbfbfb;
 	-webkit-border-radius: 3px;
 	border-radius: 3px;
@@ -40,7 +40,7 @@
 }
 
 #wp-auth-check-wrap #wp-auth-check-form {
-	background: url('../images/wpspin-2x.gif') no-repeat center center;
+	background: url(../images/wpspin-2x.gif) no-repeat center center;
 	background-size: 16px 16px;
 	height: 100%;
 }
@@ -52,10 +52,19 @@
 }
 
 #wp-auth-check-wrap .wp-auth-check-close {
-	bottom: 10px;
-	display: none;
 	position: absolute;
-	right: 30px;
+	top: 8px;
+	right: 8px;
+	height: 14px;
+	width: 14px;
+	cursor: pointer;
+	background-image: url(../images/uploader-icons.png);
+	background-repeat: no-repeat;
+	background-position: -100px 0;
+}
+
+#wp-auth-check-wrap .wp-auth-check-close:focus {
+	outline: 1px dotted #888;
 }
 
 #wp-auth-check-wrap .wp-auth-fallback-expired {
@@ -65,7 +74,7 @@
 #wp-auth-check-wrap .wp-auth-fallback {
 	font-size: 14px;
 	line-height: 21px;
-	padding: 10px 25px;
+	padding: 0 25px;
 	display: none;
 }
 
@@ -74,3 +83,12 @@
 	display: block;
 }
 
+@media print,
+  (-o-min-device-pixel-ratio: 5/4),
+  (-webkit-min-device-pixel-ratio: 1.25),
+  (min-resolution: 120dpi) {
+	#wp-auth-check-wrap .wp-auth-check-close {
+		background-image: url(../images/uploader-icons-2x.png);
+  		background-size: 134px 15px;
+	}
+}
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index eb9715d463..856f657b2f 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -3943,6 +3943,7 @@ function wp_auth_check_html() {
 	<div id="wp-auth-check-wrap" class="<?php echo $wrap_class; ?>">
 	<div id="wp-auth-check-bg"></div>
 	<div id="wp-auth-check">
+	<div class="wp-auth-check-close" tabindex="0" title="<?php esc_attr_e('Close'); ?>"></div>
 	<?php
 
 	if ( $same_domain ) {
@@ -3957,7 +3958,6 @@ function wp_auth_check_html() {
 		<p><a href="<?php echo esc_url( $login_url ); ?>" target="_blank"><?php _e('Please log in again.'); ?></a>
 		<?php _e('The login page will open in a new window. After logging in you can close it and return to this page.'); ?></p>
 	</div>
-	<p class="wp-auth-check-close"><a href="#" class="button button-primary"><?php _e('Close'); ?></a></p>
 	</div>
 	</div>
 	<?php
@@ -3974,9 +3974,9 @@ function wp_auth_check( $response, $data ) {
 
 	// If the user is logged in and we are outside the login grace period, bail.
 	if ( is_user_logged_in() && empty( $GLOBALS['login_grace_period'] ) )
-		return $response;
+		return array_merge( $response, array( 'wp-auth-check' => '1' ) );
 
-	return array_merge( $response, array( 'wp-auth-check' => '1' ) );
+	return array_merge( $response, array( 'wp-auth-check' => 'show' ) );
 }
 
 /**
@@ -4018,4 +4018,4 @@ function _canonical_charset( $charset ) {
 		return 'ISO-8859-1';
 
 	return $charset;
-}
\ No newline at end of file
+}
diff --git a/wp-includes/js/wp-auth-check.js b/wp-includes/js/wp-auth-check.js
index aa2b1ddcb0..21b3c96750 100644
--- a/wp-includes/js/wp-auth-check.js
+++ b/wp-includes/js/wp-auth-check.js
@@ -1,6 +1,6 @@
 // Interim login dialog
 (function($){
-	var wrap, check, scheduleTimeout;
+	var wrap, check, next;
 
 	function show() {
 		var parent = $('#wp-auth-check'), form = $('#wp-auth-check-form'), noframe = wrap.find('.wp-auth-fallback-expired'), frame, loaded = false;
@@ -32,7 +32,7 @@
 					if ( body && body.hasClass('interim-login-success') )
 						hide();
 					else
-						parent.css( 'max-height', height + 60 + 'px' );
+						parent.css( 'max-height', height + 40 + 'px' );
 				} else if ( ! body || ! body.length ) {
 					// Catch "silent" iframe origin exceptions in WebKit after another page is loaded in the iframe
 					wrap.addClass('fallback');
@@ -74,49 +74,34 @@
 		}
 
 		wrap.fadeOut( 200, function() {
-			wrap.addClass('hidden').css('display', '').find('.wp-auth-check-close').css('display', '');
+			wrap.addClass('hidden').css('display', '');
 			$('#wp-auth-check-frame').remove();
 		});
 	}
 
 	function schedule() {
-		check = false;
-		window.clearTimeout( scheduleTimeout );
-		scheduleTimeout = window.setTimeout( function(){ check = 1; }, 300000 ); // 5 min.
+		var interval = parseInt( window.authcheckL10n.interval, 10 ) || 180; // in seconds, default 3 min.
+		next = ( new Date() ).getTime() + ( interval * 1000 );
 	}
 
 	$( document ).on( 'heartbeat-tick.wp-auth-check', function( e, data ) {
-		if ( check === 2 )
+		if ( data['wp-auth-check'] ) {
 			schedule();
 
-		if ( data['wp-auth-check'] && wrap.hasClass('hidden') ) {
-			show();
-		} else if ( ! data['wp-auth-check'] && ! wrap.hasClass('hidden') ) {
-			hide();
+			if ( data['wp-auth-check'] == 'show' && wrap.hasClass('hidden') )
+				show();
+			else if ( data['wp-auth-check'] != 'show' && ! wrap.hasClass('hidden') )
+				hide();
 		}
+	}).on( 'heartbeat-send.wp-auth-check', function( e, data ) {
+		if ( ( new Date() ).getTime() > next )
+			data['wp-auth-check'] = 1;
 	}).ready( function() {
 		schedule();
 		wrap = $('#wp-auth-check-wrap');
 		wrap.find('.wp-auth-check-close').on( 'click', function(e) {
 			hide();
 		});
-		// Bind later
-		$( document ).on( 'heartbeat-send.wp-auth-check', function( e, data ) {
-			var i, empty = true;
-			// Check if something is using heartbeat. If yes, trigger the logged out check too.
-			for ( i in data ) {
-				if ( data.hasOwnProperty( i ) ) {
-					empty = false;
-					break;
-				}
-			}
-
-			if ( check || ! empty )
-				data['wp-auth-check'] = 1;
-
-			if ( check )
-				check = 2;
-		});
 	});
 
 }(jQuery));
diff --git a/wp-includes/script-loader.php b/wp-includes/script-loader.php
index c8ac6c66d5..300fea9874 100644
--- a/wp-includes/script-loader.php
+++ b/wp-includes/script-loader.php
@@ -113,6 +113,7 @@ function wp_default_scripts( &$scripts ) {
 	$scripts->add( 'wp-auth-check', "/wp-includes/js/wp-auth-check$suffix.js", array('heartbeat'), false, 1 );
 	did_action( 'init' ) && $scripts->localize( 'wp-auth-check', 'authcheckL10n', array(
 		'beforeunload' => __('Your session has expired. You can log in again from this page or go to the login page.'),
+		'interval' => apply_filters( 'wp_auth_check_interval', 3 * MINUTE_IN_SECONDS ),
 	) );
 
 	$scripts->add( 'wp-lists', "/wp-includes/js/wp-lists$suffix.js", array( 'wp-ajax-response', 'jquery-color' ), false, 1 );