Can I get slide-ins only on certain pages by category?

Hi.
I've read the usage manual, and searched your site and forums. I have not been able to find an answer.

Is it possible to assign a slide-in to a certain category or pages or posts? I thought they would pull into the "Show Message On:" area, but they do not. Just some of my custom taxonomies show up, but not by category.

Perhaps I need to enable some setting?

Here is what shows in "Show Message On:"

--------
any of my singular pages
any of my archive pages
home page
"Posts" post pages
"Pages" post pages
"Contributables" post pages
"Variations" post pages
"Coupons" post pages
"Events" post pages
"Venues" post pages
"Organizers" post pages
"WooFramework Internal Container" post pages
"Features" post pages
"Opportunities" post pages
"Articles" post pages
"Quotes" post pages
"Resources" post pages
--------

Thanks for your help.
-Joe-