public ConnectionDragStartedEventArgs(RoutedEvent routedEvent, object source,
ElementItem elementItem, ConnectorItem connectorItem)
: base(routedEvent, source, elementItem, connectorItem)
{
}
internal ConnectionDraggingEventArgs(RoutedEvent routedEvent, object source,
ElementItem elementItem, object connection, ConnectorItem connectorItem)
: base(routedEvent, source, elementItem, connectorItem)
{
_connection = connection;
}