static JRootPane getRootPane(RootPaneContainer f) {
  ret f == null ? null : f.getRootPane();
}

static JRootPane getRootPane(Component c) {
  ret getRootPane(getPossiblyInternalFrame(c));
}

static JRootPane getRootPane(JFrame f) {
  ret getRootPane((RootPaneContainer) f);
}