Please upgrade to 2.3 here.
The 2.2 and earlier branches are no longer being updated.
Showing discussions in groups of categories
Categories can be grouped under "parent" categories, which is a handy thing to be able to do to help with organisation of categories.
However, that grouping appears to be used only by the categories module that is displayed in the sidebar, and does not go any deeper than this presentational aspect. For a user you have two options for displaying categories: all of them, or just one.
What I would like to be able to do, is display (and fetch through RSS) all the discussions under a given parent category. That means all discussions for categories that I have permission to see, that share the same parent category. Looking through the code, it seems that this would be an involved change, because the code is pretty much locked down to "all categories or just one" at many levels (I was hoping it was a simple change).
Is this something that anyone has created a plugin for, or has any plans to change?