On the View tab in the dialog box of the ribbon command File | Properties 
, you can make settings for the appearance of the document on the screen.
Objects section
As described in Hiding objects, you can make inserted objects invisible on the screen and/or on the printed page.
You can still make such objects visible again by means of these two options:
▪Show invisible objects: If you enable this option, any object whose Visible property is disabled becomes visible on the screen.
▪Print unprintable objects: If you enable this option, any object whose Printable property was disabled will also be printed again.
Both options are disabled by default.