From 3c044eba6fb0025bb2ea8e9cd44b5808f7fb6182 Mon Sep 17 00:00:00 2001
From: koopersmith <koopersmith@1a063a9b-81f0-0310-95a4-ce76da25c4cd>
Date: Fri, 25 May 2012 22:43:11 +0000
Subject: [PATCH] Theme Customizer: Correctly use custom-background class in
 theme preview. See #19910.

git-svn-id: http://core.svn.wordpress.org/trunk@20919 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/js/customize-preview.dev.js | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/wp-includes/js/customize-preview.dev.js b/wp-includes/js/customize-preview.dev.js
index 6d2540f90..36c4a6a85 100644
--- a/wp-includes/js/customize-preview.dev.js
+++ b/wp-includes/js/customize-preview.dev.js
@@ -81,15 +81,28 @@
 		});
 
 		api.when.apply( api, bg ).done( function( color, image, position_x, repeat, attachment ) {
-			var style = $('#custom-background-css'),
+			var body  = $(document.body),
+				style = $('#custom-background-css'),
 				update;
 
-			if ( ! style.length )
+			// If custom backgrounds are active and we can't find the
+			// default output, bail.
+			if ( body.hasClass('custom-background') && ! style.length )
 				return;
 
+			// Create the CSS container if it doesn't already exist.
+			if ( ! style.length )
+				style = $('<style type="text/css" id="custom-background-css" />').appendTo('head');
+
 			update = function() {
 				var css = '';
 
+				// The body will support custom backgrounds if either
+				// the color or image are set.
+				//
+				// See get_body_class() in /wp-includes/post-template.php
+				body.toggleClass( 'custom-background', !! ( color() || image() ) );
+
 				if ( color() )
 					css += 'background-color: #' + color() + ';';