private void OnShiftRight(object o, EventArgs args)
 {
     Command command = new PathShiftCommand("Path shifted forward", path, 1);
     command.Do();
     UndoManager.AddCommand(command);
     Redraw();
 }
 private void OnShiftLeft(object o, EventArgs args)
 {
     Command command = new PathShiftCommand("Path shifted backwards", path, -1);
     command.Do();
     UndoManager.AddCommand(command);
     Redraw();
 }