This action ensures that absolutely ALL objects are now visible. That means you are quite sure that none of the objects anywhere on the site has been hidden. This is a sweeping command that will reassure you it has rigorously examined your entire model; and now all objects in the model are visible
This does not change the state of the selection set. That means if some objects were selected; they would continue to remain selected.
Press F1 inside the application to read context-sensitive help directly in the application itself