Revert to last published state - "unpublished changes in editor"

As with most people, testing layouts in Dashboard is very much trial and error, but the current version doesn't allow you "revert to last published state" and the unpublished changes in editor message is permanently pinned to the top.

There doesn't appear to be a way of reverting to last published state, and hiting edit takes you back to the edited test version.

This needs to be a feature that's possible for the Explore app to be useful.