Is there any reason why you cant change who asked a question in the backend, it just does not make sense.

sorry about that, i was not clear with the second. I meant that if you selected a subcategory (as you kindly explained). For example, my site has a menu link for multiple categories. This way i can create multiple forums. In this case, it would be nice to have the home page show all subcategories of the respective category.

Not sure how that happened. It is designed to show all sub-categories of the category selected on home page. You would see something like this:

All Categories - Selected Category Name

Sub Cat (10/21)             Sub Cat 2 (2/6)            Sub Cat 3 (3/5)

What is the CA version you are using? If the above functionality is missing, there is something went wrong, can you send me your website details through contact us form?

i am using 1.8.6, is this a recent change you made because i just updated to 1.8.6