[2] The FOX toolkit has been released under the GNU Lesser General Public Licence.

Since then, Jeroen van der Zijp maintains the core library and test applications, with the help of user community.

[citation needed] FOX uses a technique similar to the Java Swing-style approach to display a graphical user interface to the screen, using only graphical primitives available on that platform, as opposed to the original Java AWT-style approach which used native widgets.

Also, certain native platform features may not be available immediately, such as comprehensive printing support or internationalized input handling, because they will need to be re-implemented in a cross-platform way before they can be used in FOX.

Each message is composed by a selector that identifies its kind and an id that is unique and provided by the widget's enumeration.