Diagram Preferences

The Diagram Preferences dialog lets you modify some options for the Diagram Panel. To access the Diagram Preference dialog select Windows > Preferences... from the menu. Then find Diagram under TopBraid Composer. Alternatively, you can use the corresponding Edit Preferences... button in the Diagram View.

Currently, the options you can select are limited to:

Show root class defines whether rdfs:Resource and owl:Thing should be shown in the diagram. If you are developing OWL ontologies, all classes you define are subclasses of owl:Thing. When selected owl:Thing will be displayed on each diagram. Every class shown in the diagram will have a subclass relationship path connecting it to owl:Thing. For classes that have only a handful of relationships with the other classes, this may work well. However, in many cases presence of owl:Thing makes diagrams overly complicated.
Show associations defines whether the thin lines derived from range definitions shall be shown in the diagram.
Automatically expand superclass relationships specifies whether the system should pre-populate the diagram with superclass relationships when the diagram is opened first.
Automatically expand relationships via restrictions specifies whether the system should pre-populate the diagram with those relationships derived from OWL restrictions when the diagram is opened first.
Show attributes specifies whether attributes shall be displayed inside of the boxes.
Show disjointness defines whether owl:disjointWith relationships shall be displayed (with red lines).
Use vertical and horizontal edges only will make sure that all edges only have 90 degree angles. This sometimes makes diagrams look nicer, but may also lead to edges that overlap existing nodes.

You can furthermore adjust the horizontal and vertical scaling to define how much space the diagram shall cover

If you are using the diagram for editing, you can also specify whether new Associations shall result in rdfs:domain/rdfs:range or owl:allValuesFrom restrictions.