Focus on running application window in single instance mode when user tries to run second instance. This greatly enhances user's experience.
Currently singleInstance/title option is not enough to activate program window if there are several windows with such title e.g. Explorer window with program folder opened. In such case last recently used window is brought to front which may not be program window.
Allowing to use window class additionally to window title option would resolve this problem in most cases.
e.g. add singleInstance/windowClass.
the issue was copied to http://code.google.com/p/jliftoff/issues/list