In the Diagram Style window, you can define diagram-level appearance settings, and default settings for the blocks and connectors within the diagram. These settings can be saved in a diagram skin and reused with other diagrams.
To open the Diagram Style window, right-click the diagram (not blocks) and choose Diagram Style.
This window consists of multiple pages. The number and type of pages depend on the type of diagram that you are working with. Settings that can be defined are divided into two groups: Diagram and Defaults.
At the diagram level, you can define the appearance of the diagram sheet and those aspects of the appearance of diagram components (i.e., blocks and connectors) that cannot be configured at the individual component level.
You can define the default appearance settings for diagram components (i.e., connectors, blocks and annotations). See Defaults for Blocks and Connectors.