public void alignBottom(ArrayList<Element> selectedElements) {
        /* Most lowest */
        int minBottom = Integer.MIN_VALUE;
        int currentBottom = 0;
        for (Element e : selectedElements) {
            if (e instanceof AbsPlace) {
                AbsPlace a = (AbsPlace) e;
                currentBottom = a.getY() + a.getHeight();
            }
            if (e instanceof Node) {
                Node n = (Node) e;
                currentBottom = n.getY() + n.getHeight();
            }
            if (e instanceof Transition) {
                Transition t = (Transition) e;
                currentBottom = t.getY() + t.getHeight();
            }

            if (currentBottom > minBottom) {
                minBottom = currentBottom;
            }
            // Arc is nothing //
        }
        for (Element e : selectedElements) {
            if (e instanceof AbsPlace) {
                AbsPlace a = (AbsPlace) e;
                a.setY(minBottom - a.getHeight());
            }
            if (e instanceof Node) {
                Node n = (Node) e;
                n.setY(minBottom - n.getHeight());
            }
            if (e instanceof Transition) {
                Transition t = (Transition) e;
                t.setY(minBottom - t.getHeight());
            }
            // Arc is nothing //
        }
    }