Razor _Layout resolution and RazorViewManager refactor

I hit what I think is a bug the other day:

    /Views/_Layout.cshtml
    /Views/Public.cshtml
    /Views/Admin/_Layout.cshtml
    /Views/Admin/Dashboard.cshtml

The dashboard page was resolving the parent public layout, rather than the sibling admin layout. I wrote the test and it didn't reproduce it, but after expanding the test suite I realized it depends on the order the layout files are added, so these tests don't reproduce the above scenario exactly, but they reproduce other issues. And there's definitely more test combinations that can easily be added now.

No fix yet, I just wanted to confirm view page layouts should cascade just like content page layouts, even though view pages themselves map to DTOs purely on name and folder structure is not important, correct?