When the current level of the diagram is so large that it doesn’t all fit in the viewable part of the window, you can:
• Hold down the CTRL key and roll the mouse wheel. Forward rolling zooms in on the diagram; rolling backward zooms out.
• Click on the toolbar buttons to enlarge or shrink diagram components.
• Use the scroll bars to pan to the parts of the diagram you want to view. If you right-click over a scroll bar, a Windows navigation pop-up menu appears. Select the navigation option that corresponds with what you want to do.
Typically, larger, more complex diagrams should be divided into subsystems and encapsulated in compound blocks.