On the View Control Bar, click (Reveal Hidden Elements).
The Reveal Hidden Elements icon and the drawing area display a color border to indicate that you are in Reveal Hidden Element mode. All hidden elements display in color, and visible elements display in half-tone.
Example
To unhide hidden elements
Select the element.
Do one of the following:
Click Modify | <Element> tabReveal Hidden Elements panel (Unhide Element) or (Unhide Category).
Right-click the element, and click Unhide in ViewElements or Category.
Note: The Unhide Element and Unhide Category options become active when you select an element that was hidden by element or, a category that was hidden by category.
On the View Control Bar, click to exit Reveal Hidden Elements mode.