An implementation as a Java application is presented for demonstrating the flexible widget layout. Click the following link and download a zip file, and then unpack the file and exexute "FWL5.0.jar" by double clicking. This window executes re-layout corresponding to your resize operation of the window. At this time, you can find widget selections (switching) are performed.
For this demo, you need to install Java Runtime Environment Version 8 or later.