It seems like this should be simple, but I can't seem to get it to work. I added some widgets to "Sidebar Blog" and they appear under Portfolio items as well. I've tried creating a special widgets area for Portfolio, as well as one for category "Materials" which is assigned to all Portfolio items, but no luck. It occurs to me that it may not work that way, but I can't seem to find any other way to do it. Hopefully I'm missing something obvious.
Here is an example. The sidebar items refer only to blog posts: