automatic update of price when different variant is selected

I have created several products that have different prices and then associated those products with a product display as product variations as described here - https://drupalcommerce.org/user-guide/product-attributes-variations. When I view the product display and select a different variant from the drop down the price does not update. I wanted to test if it was an issue related to the Jollyness theme so I switched to a the Bartik theme which is included with Drupal and this fixed the issue. When using the Bartik theme the price updated when I selected a different variant from the drop down. Here is an example of what I expected to happen. Notice if you select a different size for this Laptop bag the price automatically updates without needing to refresh the page. http://demo.commerceguys.com/ck/bags-cases/commerce-guys-laptop-bag Thanks for you help.
To fix this issue I made a copy of jollyness/templates/node--product_display.tpl.php, put it in jollyness_sub/templates and changed line 98 from <?php print strip_tags(render($content['product:commerce_price']));?> to <?php print render($content['product:commerce_price']);?>
Thank you in advanced. We will check and update on package. Cheers.