code: public static void install() {
  		final String os = System.getProperty("os.name");
  		final boolean macintosh = os != null && os.indexOf("Mac") != -1;
  		if (macintosh) {
  			return;
  		}
  
  		final PopupFactory factory = PopupFactory.getSharedInstance();
  		if (factory instanceof ShadowPopupFactory) {
  			return;
  		}
  
  		PopupFactory.setSharedInstance(new ShadowPopupFactory(factory));
  	}
docs: Installs the ShadowPopupFactory as the shared popup factory
  on non-Mac platforms. Also stores the previously set factory,
  so that it can be restored in <code>#uninstall</code>.<p>
  
  In some Mac Java environments the popup factory throws
  a NullPointerException when we call <code>#getPopup</code>.<p>
  
  The Mac case shows that we may have problems replacing
  non PopupFactory instances. Therefore we should consider
  replacing only instances of PopupFactory.
  
  @see #uninstall()