Add to cart pop up not showing

Hi there,
i have problem with my OC ver 3.0.2.0
when i add to cart the product, the pop up notification is not sowing
but there's strange change after the add to cart process, the screenshot is on attachment below




my example url : http://store.mostlyjazz.id/index.php?ro ... uct_id=279
as you can see there's a circle button with a square inside it
anyone can help this issue?
Thanks before

Screenshot is not visible.