svoid setTitledBorderFontSize(JComponent c, float fontSize) {
  if (c == null) ret;
  swing {
    javax.swing.border.TitledBorder b = optCast(javax.swing.border.TitledBorder.class, c.getBorder());
    if (b != null) {
      Font font = b.getTitleFont();
      b.setTitleFont(font.deriveFont(fontSize));
    }
  }
}