I'm using Zencart 1.3.7 (had same problem under 1.3.6), and the Update Cart button doesn't update the cart. The form submits, but the quantities are not updating. I'm using the button at the bottom only (state 2 in the Stock options).
I haven't changed tpl_shopping_cart_default.php at all.
Does anyone have any ideas? I've searched this forum and the documentation, to no avail.
If any code samples or the URL of the site would be helpful (I'd rather not give it out publicly yet, as it's not done but there are products up), please let me know and I'll be happy to provide them.
Thanks in advance,