Use a Menu (

) node to customize the context menu of the physics interface. This particular node adds a submenu.
To add a Menu node, right-click the
Physics Interface or
Multiphysics Interface nodes and add it from the context menu. Also right-click the
Menu node to add a
Menu Item node or another
Menu node, which acts as a submenu.
In the Settings window for
Menu, enter a
Title of the menu in the text field.