The view displays all elements of type `DemoPlain:A` at the top level. This type is not a structure type. The objects that are assigned to the reference `DemoPlain:DemoPlain.A#typedSetOrdered` are displayed as sub-elements of . `SecurityStructure#ROOT` is used as the technical root node for the tree display, but is not displayed. The creation of top-level nodes is implemented via a separate command that always creates them in the context of `SecurityStructure#ROOT`.