A View menu and a right-click diagram menu entry is available that reads:
Hide relationship lines not attached to selected node objects
System Architect will enter a state whereby all Relationship lines are hidden except those attached to selected nodes. In this state, the menu entry change to:
Reveal all Relationship lines which restores the state to the normal condition
This State applies to the current diagram in the current edit session. It is retained through all changes to the diagram, including undo and redo. It is not considered a change to the diagram, so it is not un-doable or re-doable. The normal state is reinstated when the diagram is closed or the Reveal all Relationship lines menu entry is invoked. When the diagram is opened, whether normally or in a recovery, regardless of its state when it was last closed, the normal state will pertain and all Relationship lines will be visible.