Diagram overview
Bar for the diagram area. Displays the diagram in an overview. You can quickly change the visible area of the modeling area by moving the frame displayed. The size of the frame is determined by the size of appearance that you set in the model properties. The lower the percentage you enter in the Size of appearance box, the larger the visible area and thus the frame of the diagram overview, and vice versa.
If you change the size of the diagram in the diagram window (Ctrl + mouse wheel), the size of the frame is adjusted automatically.