404 when selecting (no parent)

I want to make a page with no parent that will basically only be accessible via direct permalink. I’ve done this successfully multiple times (most recently was in July) by selecting “no parent” in the Page Attributes and unchecking the “Include this Page in the list of pages” box.

Now when I try to view a new page created in the same way, I get a 404 Page not found. I figured out that if I give the page a parent, I can view it – but nothing I do allows me to view the new page if I have “no parent” selected.

Using Twenty Ten 1.0 theme – not sure if that matters.

Thoughts?