Use the modes in the Designer to develop your diagram
as follows:
Work in Style Editing mode to define
your style rules
Work in Preview mode to test the resulting
behavior of the diagram component as it would be in an application.
Work in Diagram Editing mode to build
up a diagram one node or link at a time, and to position nodes and
links in a diagram manually by dragging them. Note that editing the
diagram will modify the data model.