It is not a regression.

JAB does not work if it is enabled after Java application has been launched.
Also, JAB does not work after following operations:

%JAVA_HOME%\jre\bin\jabswitch.exe /enable
%JAVA_HOME%\bin\java -jar demo\jfc\SwingSet2.jar
          //NOW JAB WORKS!
%JAVA_HOME%\jre\bin\jabswitch.exe /disable
          //NOW JAB NOT WORKS as expected!
%JAVA_HOME%\jre\bin\jabswitch.exe /enable
          //NOW JAB NOT WORKS BUT It is NOT expected!