private void fillPanel(JPanel panel) {
        panel.add(createIconsRow(NotificationType.INFORMATION, true));
        panel.add(createIconsRow(NotificationType.INFORMATION, false));
        panel.add(createIconsRow(NotificationType.WARNING, true));
        panel.add(createIconsRow(NotificationType.WARNING, false));
        panel.add(createIconsRow(NotificationType.ERROR, true));
        panel.add(createIconsRow(NotificationType.ERROR, false));
      }
private void fillPanel(JPanel panel)