About view modes

You can change the visibility of the document window using the Mode buttons at the bottom of the toolbox or by choosing commands from the View > Screen Mode menu. When the toolbox is displayed in a single column, you can select view modes by clicking the current mode button and selecting a different mode from the menu that appears.

Normal Mode: Displays artwork in a standard window with all visible grids and guides showing, non-printing objects showing, and a white pasteboard.
Preview Mode: Displays artwork as if it were output, with all non-printing elements suppressed (grids, guides, non-printing objects), and the pasteboard set to the preview background color defined in Preferences.
Bleed Mode: Displays artwork as if it were output, with all non-printing elements suppressed (grids, guides, non-printing objects), the pasteboard set to the preview background color defined in Preferences, and any printing elements within the document's bleed area (defined in Document Setup) showing.
Slug Mode: Displays artwork as if it were output, with all non-printing elements suppressed (grids, guides, non-printing objects), the pasteboard set to the preview background color defined in Preferences, and any printing elements within the document's slug area (defined in Document Setup) showing.