A lot of very GUI demanding programs have been written in Allegro CL, including CAD systems, 3d design system, ... It came very early with a form-based GUI des

A lot of very GUI demanding programs have been written in Allegro CL, including CAD systems, 3d design system, ... It came very early with a form-based GUI designer. Allegro CL addresses with their GUI facilities explicitly MS Windows and Unix/Linux environments.