// runnable takes an argument
static <A extends JComponent> A onLeftClick(final A c, fO runnable) {
  swing {
    c.addMouseListener(leftClickMouseAdapter(runnable));
  }
  ret c;
}

// runnable takes no args
static TrayIcon onLeftClick(final TrayIcon c, final O runnable) {
  swing {
    c.addMouseListener(leftClickMouseAdapter_noPt(runnable));
  }
  ret c;
}


static <A extends JComponent> A onLeftClick(fO runnable, A c) {
  ret onLeftClick(c, runnable);
}

Began life as a copy of #1005614