Hi together, Although this is slightly off-topic I wanted to throw FLTK <http://www.fltk.org/index.php> into the ring. It is certainly not as modern as Qt5, but it is fast and light! One also needs Cxx.jl since FLTK is a C++ library, but it is pretty conservative (no templates etc), so it shouldn't be too hard to wrap it (I can post some proof of principle code, but my Cxx is currently broken, so I can't test it further).
Anyways, I think the topic of widget toolkits can be very subjective and controversial. I just wanted to mention FLTK as an option, but definitely don't want to start a fundamental discussion about different WTKs. Best, Alex.
