Hi,
I’m trying to add a menu navigation without child categories with wp_list_categories().
All is fine but I have a problem with order (orderby).
If I open the file wppizza-navigation.php, i can see this code :
echo wp_list_categories( $args );
I added print_r($args); , and I have :

Array ( [taxonomy] => wppizza_menu [orderby] => name [show_count] => 0 [pad_counts] => 0 [hierarchical] => 1 [title_li] => [depth] => 0 [exclude] => [child_of] => 0 [show_option_none] => Nothing here [hide_empty] => 1 [echo] => 0 )

I copied this arguments to make my own function :

function my_nav(){
$myargs=array ( 
'taxonomy' => 'wppizza_menu' ,
'orderby' => 'name' ,
'show_count' => 0 ,
'pad_counts' => 0 ,
'hierarchical' => 1 ,
'title_li' =>'' ,
'depth' => 1  ,
'child_of' => 0 ,
'show_option_none' => 'Nothing here' ,
'hide_empty' => 1 ,
'echo' => 0 ,
);
echo wp_list_categories( $myargs );
}

With your function, the order is right, like in Admin > wppizza > categories, but with my function the order is wrong. I think ‘orderby’ = >’name’ is the problem, so I tried different value, but I can’t find the right. And I searched in the Database to looking for the variable of order. But no result. I don’t understand why the parameter ‘orderby’ => ‘name’ is ok in your function.
Do you know how can I have the right order with wp_list_categories() ?
Thanks !