Yes, A, B and C has the same superclass.
What we want is to have one start node that should have 1 outgoing link,
one normal node that should have 0-* outgoing and incoming links and one
final node that should have 1 incoming link. The link type should always
be the same, it should be up to the node to decide or "know" whether it
should accept an incoming/outgoing link.
The reason that we chose to have three types of nodes is because they
should not look the same when drawn in the editor.
It seem as though the editor has "understood" the rules of what kind of
nodes that can be combined in a certain way but the actual creation of the
link is not done. We think it is the connection between the graphic
display part and the controller - get/set variables that is "broken"
rather than the actual drawing of the link. The link is not "saved"
anywhere so when "repaint" or whatever is done there is no link
information to paint.