If you have an ideas portal that contains multiple products, each product creates its own idea category section along the left hand side of the portal.
The category sections are organized based on the order in which the products exist in your Aha! account and can only be re-ordered by re-ordering your entire account structure - which functionally only works as a work around if you have a single product line.
The default should be alphabetical ordering.
Products in the idea portal (under the Filter by Category heading) are now ordered in alphabetical order.