full-width page templates still have sidebar

I’m using Portfolio Press (actually, Portfolio Press Custom but I’ve made no changes), and added the Portfolio Post Type plugin. I created a portfolio page and populated it with Portfolio items. It seemed to be working fine, but when I tried to use a page template that’s full width, it still shows the sidebar.

I tried Full-width Page, Full-width Image and Gallery Posts, and Full-width Portfolio and all three made no change to the actual page. The sidebar with Search, Archives, and Meta is still sitting there.

If I disable the Portfolio Post Type plugin and use posts (image format) again, the full-width templates remove the sidebar. So it seems to be the plugin that won’t let me use page templates.