private void visualizer_ConnectionCreated(object sender, ConnectionCreatedEventArgs e)
{
try {
Relation relation = AddRelation(e.First, e.Second, e.RelationType);
visualizer.AddRelation(relation, true);
}
catch (ArgumentException ex) {
MessageBox.Show(ex.Message, "error",
MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
