FOX is a C++-based library for graphical user interface development.
FOX supports modern GUI features such as drag-and-drop, tooltips, tab
books, tree lists, icons, multiple document interfaces (MDI), timers,
idle processing, automatic GUI updating, as well as OpenGL/Mesa for 3D
graphics. Subclassing of basic FOX widgets allows for easy extension
beyond the built-in widgets by application writers.