In module uc_order, function uc_order_history, there is a small block of code which is restricted to users with "view all orders" access.
if (user_access('view all orders')) {
$link .= '<span class="order-admin-icons">'. uc_order_actions($order, TRUE) .'</span>';
}If one follows the call to function uc_order_actions, one sees that every block in uc_order_actions which produces some output are limited by their own user_access function calls.
user_access('view all orders')
user_access('edit orders')
user_access('delete orders')
user_access('delete any order')The result is that you can't easily hook into hook_order_actions, because it is by design limited to only those users with "view all orders" access. Also, any action will rely on the user having "view all orders" access including any other access restrictions one would want to use. On top of this nothing is changed if the first check is removed, because every action listed have it's own user access check.
I just commented out the check in function uc_order_history and included this line "$actions = array();" to function uc_order_actions - that one should have been there anyway (non-initialized variable...).