Background color not changing dynamically with WP3.4 customize panel

Hi and thanks for any help in advance.

I’m trying to add the new custom-background option to my theme. I never used the previous (pre 3.4) custom background technique so I’m starting from scratch.

The problem I’m encountering is that the color is not changing dynamically with the theme customize panel, though it works once I’ve clicked “Save & Publish”.

The steps I took to include it were declaring in functions.php:

$defaults = array(
	'default-color' 		=> 'fff',
	'default-image' 		=> get_template_directory_uri() . '/img/background.jpg',
	'wp-head-callback'  		=> '_custom_background_cb',
	'admin-head-callback'    	=> '',
	'admin-preview-callback'	=> '',
);

add_theme_support( 'custom-background', $defaults);

Then added wp_head(); to my header followed by body_class(); to my body tag, all of which works perfectly.

I don’t know if I’ve missed something but the Customize Panel is not changing the color styling of body.custom-background selector until save.

Thanks again.