View Tab

When you navigate to a page while logged in as Manager, the View tab is (in most cases) the default "active" tab. 

Generally speaking, the view tab simply shows you the same thing a regular (i.e. non-logged-in) user would see.  If you are performing some administrative function (e.g. adding a page, submitting a document) and realize you want to stop that and simply return to a regular user's view of the site, use the View tab.