Use the Structure view as a Preview, that allows you to get a "10,000-feet" look on a diagram. The shadow area represents the visible part of a diagram. As you zoom in or out, or change the shape of the IntelliJ IDEA windows, the size of the shadow area changes accordingly.
To enable the diagram preview
Open the Structure tool window.
In the Preview pane, the following actions are available:
Keeping the mouse button pressed, move the shadow area to obtain the desired view.
Select one or more nodes in the diagram, and the corresponding nodes in the Preview are marked dark gray.