The Zoom function lets you select a sub-area of the diagram and re-display it at full window size. When you do this, the original diagram disappears, and the blown-up sub-area appears.
To use the Zoom function, do the following:
A spot appears at your cursor point.
The spot becomes a rectangle that grows in length and width as you move the cursor. The area inside this rectangle is the sub-area you are requesting.
The original diagram disappears, and the sub-area, blown up to window size, takes its place.
To display the original graphic again, choose Settings® Complete picture.
To display the last sub-area before the current one, choose Settings® Last zoom.
The following figure shows a zoomed view of the drawing shown in the Overview section.