protected List refreshTicksVertical(Graphics2D g2,
                                        Rectangle2D dataArea,
                                        RectangleEdge edge) {

        List result = new java.util.ArrayList();

        Font tickLabelFont = getTickLabelFont();
        g2.setFont(tickLabelFont);

        if (isAutoTickUnitSelection()) {
            selectAutoTickUnit(g2, dataArea, edge);
        }
        DateTickUnit unit = getTickUnit();
        Date tickDate = calculateLowestVisibleTickValue(unit);
        //Date upperDate = calculateHighestVisibleTickValue(unit);
        Date upperDate = getMaximumDate();
        while (tickDate.before(upperDate)) {

            if (!isHiddenValue(tickDate.getTime())) {
                // work out the value, label and position
                String tickLabel;
                DateFormat formatter = getDateFormatOverride();
                if (formatter != null) {
                    tickLabel = formatter.format(tickDate);
                }
                else {
                    tickLabel = this.tickUnit.dateToString(tickDate);
                }
                TextAnchor anchor = null;
                TextAnchor rotationAnchor = null;
                double angle = 0.0;
                if (isVerticalTickLabels()) {
                    anchor = TextAnchor.BOTTOM_CENTER;
                    rotationAnchor = TextAnchor.BOTTOM_CENTER;
                    if (edge == RectangleEdge.LEFT) {
                        angle = -Math.PI / 2.0;
                    }
                    else {
                        angle = Math.PI / 2.0;
                    }
                }
                else {
                    if (edge == RectangleEdge.LEFT) {
                        anchor = TextAnchor.CENTER_RIGHT;
                        rotationAnchor = TextAnchor.CENTER_RIGHT;
                    }
                    else {
                        anchor = TextAnchor.CENTER_LEFT;
                        rotationAnchor = TextAnchor.CENTER_LEFT;
                    }
                }

                Tick tick = new DateTick(tickDate, tickLabel, anchor, 
                        rotationAnchor, angle);
                result.add(tick);
                tickDate = unit.addToDate(tickDate);
            }
            else {
                tickDate = unit.rollDate(tickDate);
            }
        }
        return result;
    }