Hello,
I don't know if you still need an answer to this old topic, but as I was struggling to find a solution on this forum here what i did on my 1.6.0.9:
file:
classes/Category.php
line 507:
'.($sql_sort == '' && $use_shop_restriction ? ', category_shop.`position` ASC' : '').'
becomes:
'.($sql_sort == '' && $use_shop_restriction ? ', cl.`name`, category_shop.`position` ASC' : '').'
hope it helps!