I'm using 1.3.8a

I havent done any upgrading recently.

I know there is a setting somewhere in Admin, but I am totally missing it.

How do you set the categories so that if you click on a main category and you have sub-categories, the subs show up on the main category's page.

IE I have yarn as a main category, under that I have by Brand, and By Yarn Weight.

Under By Brand I have 2 different brands so far.

So, for example, when I select By Brand, I should see both brands on the page as well as in the navigation on the left side. If you want to see what I mean

http://www.greatyarns.com/shop

If you click on Yarn and then by brand, you will notice that nothing shows up on the page. But the navigation shows the 2 brands.

What am I missing?