In the Diagrams menu, you can configure the default visibility settings and layout for diagrams.
Select the desired layout from the Default layout list. Node elements in newly created diagrams will be arranged according to the selected layout.
Select scope from the Default scope list. Specifying a scope helps you avoid showing in diagram the unnecessary hierarchies. You can define scopes for your project in the Scopes page of the Settings (Ctrl+Alt+S) dialog.
Fit content after layout
If this checkbox is selected, then after applying a layout selected on the diagram context menu, all diagram elements will be resized to fit into the current diagram area. In diagram, use the toolbar button.
Do relayout when new elements were added
If this checkbox is selected, diagram layout will be performed automatically after adding new elements.