Selection behaves strangely when navigating between different versions of a page

[sfnelson]

E.g. when you have an index action and an archived action, the same form is preserved between both because it's marked turbo-permanent. This includes the buttons, which should change.

[sfnelson]

We have changed the selection form so that it doesn't try to remember inputs. This makes it a lot more robust but slightly less useful. I've left pending specs to describe the desired behaviour if we come back to this.