Show Diagram Properties (Visual Database Tools)
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Analytics Platform System (PDW)
You can display properties for a database diagram in the Properties window.
To show database diagram properties in the Properties window
Open Database Diagram Designer.
Make sure that no objects are selected in Database Diagram Designer by clicking anywhere within the designer except on an object.
From the View menu, click Properties Window.
The properties for the diagram are now visible in the Properties window.