When a project or a Milestone is archived, it may happen that old links go to their Workboard, their Reports pages, etc., and moreover, these pages are often without content (since everything has been resolved, and most people keeps default filters to hide resolved things).

We should figure out how to make it clearer that you are visiting a sub-page of an archived project, making sure that every sub-page states a visible "ARCHIVED" badge, or something like this.