static void setInternalFrameContents(final Component c, fO contents) {
  swing {
    JInternalFrame frame = getInternalFrame(c);
    if (frame == null) ret;
    frame.getContentPane().removeAll();
    frame.getContentPane().setLayout(new BorderLayout);
    if (contents != null) frame.getContentPane().add(wrap(contents));
    revalidate(frame);
  }
}

Began life as a copy of #1003379