A Relation Graphics object is used to represent a Relation within a Diagram. i.e. it holds display properties like for font and color that are used to draw the Relation. A Diagram owns a Relation Graphics object for each Relation displayed in the Diagram.
When you select a Relation in a Diagram, ModelRight automatically adds the corresponding Relation Graphics object to the selection. That is why in the Property Browser you see the both the Relation Property Pages as well as the Graphics Property Page (for the Relation Graphics object). Similarly, when you select a Relation in the Model Explorer, ModelRight automatically adds its associated Relation Graphics object from the active Diagram (if there is one) to the selection.
Inherit - select which Relation Graphics Template you want the current Relation Graphics object to inherit properties from.
Graphics Only - click the Graphics Only link to select just the Relation Graphics object. You may need to do this to reset its properties.
Diagram - a link to the Diagram object that owns the Relation Graphics object.
Make Same In Other Diagrams - copies the current Graphics properties to the corresponding Graphics objects in all the other Diagrams.
The Default Relation Graphics Template
By default, a Relation Graphics object inherits from a Template called the Default Relation Graphics. So to change a display property for all Relations in all Diagrams, simply select the Default Relation Graphics object and make the change. You can select the Default Relation Graphics object by:
1.going to the Templates tab in the Model Explorer and selecting the Default Relation Graphics object in the Relation Graphics Template category
2.selecting a Relation in a Diagram, and then selecting the Inherit link in the Graphic tab
3.selecting 
in the Shortcut Taskbar
If you right click on the background of the Diagrams section of the Model Explorer you can select Display Graphic Objects to view these objects in the Model Explorer. If you select one of these Graphic objects, you can view and modify the properties of the selected Graphics object in the Property Browser.