filter not show up on category page

I installed trial 3.3. I want to achieve something like http://www.winerack.co.uk/en/all-wines. But there are two problems:
1. ajax filter never shows up on category page, instead, i have to select a subcategory, for example, red wine, now it will show up. My question is how to show ajax filter when I click category, for example, all wine, just like what's done on winerack website.
2. On winerack website, it grays out the attributes if not available in the filter selection. However, in my installation, ajax filter will hide the attributes instead of gray them out.
3. On your documentation, you said ajax filter setting attribute "Include Products From Subcategories", but I cannot find it in my installed trial ajax filter plugin settings. Maybe that is why it caused the problem in my first question?

I figured out #3. I was able to update xml file directly.
back to #1, to show ajax filter when clicking a category, it seems I need to make a product belong to both the category and the sub-category. Can anyone shred some light on what's a better way to do that? Thanks!

Hi shellyshao,

There is no need to add the products from a subcategory to the parent category if you want to show them in parent category. You simply need to enable a setting from the administration from Configuration -> Settings -> Catalog Settings. Then check the "Include products from subcategories" checkbox and save the settings.

Hope this helps!

Thanks