Turbo Vision as introduced in Turbo Pascal 6 (C++ version came later), was a great way to learn OOP on MS-DOS, the other being Clipper 5.

Besides a nice OOP architecture, collections, iteration with callbacks, serialization, in a nice AOT compiled language with blazing compile times.

Kind of tragic what we could get in 1992, in 640 KB, in a single tasking operating systems, and how bad so many "modern" frameworks happen to be by comparison, regarding the whole development experience.