Fltkhs [1] was the best ever experience I've had while doing small/auxiliary GUI utilities. Now using NWG [2] for that (UI forms examples [3]) and it is so much less elegant and so much more verbose than Fltkhs. Resulting lean EXEs without any bundled runtime are nice though.

[1] https://github.com/deech/fltkhs

[2] https://github.com/gabdube/native-windows-gui

[3] https://github.com/wiltondb/wiltondb/wiki/WiltonDB-Data-Tran...