private void ensureListRowsHeight() {
        Object prototype;
        if ((listRenderer != null)
                && (listRenderer.getUserRenderer() == null)) {
            prototype = choicesList.getPrototypeCellValue();
            // we need to change the prototype. The jlist will not update its
            // cell height if the prototype does not change
            prototype = "X".equals(prototype) ? "Z" : "X"; //NON-NLS
        } else {
            prototype = null;
        }

        choicesList.setPrototypeCellValue(prototype);
        historyList.setPrototypeCellValue(prototype);
    }
private void ensureListRowsHeight()