Products Sort Within Category

This addon provides the ability to define the default order in which products within a category are displayed in the catalog.
It is designed to minimize core changes, but some are necessary to change the query in index.php.
Another optional core change displays the products in the same order admin/categories.php.
The sorting order is maintained on a separate admin page – Sorting Order Manager.
If you also recommend sorting order for individual products within Admin/Categories, I recommend a separate Modular Admin Category addon that dies and can do more already.