Cart Contents Empty In Sidebar

[dmoore]

I'm displaying the cart contents in the sidebar but it is not showing up for guests, only logged in users.

Here's how I'm getting the contents:
$products = $_SESSION['cart']->get_products();

This works for logged in users all the time.

It only works for guest users when they are on main_page=shopping_cart.

I've looked at the header in the shopping cart template but it gets the contents the sawe way: $products = $_SESSION['cart']->get_products();

Why does it only work for guests on main_page=shopping_cart and not other pages and how do I fix it?