Trying to defer to native widget rendering per platform was a mistake, and every time I've touched wxWidgets in the past decade and a half I've regretted it.
FLTK on the other hand is ugly as sin, but I've found it reliable enough to not act in surprising ways, and it's also small enough to where you can vendor it and build it alongside your program.
I'll trade you wxWidgets for FLTK.
Trying to defer to native widget rendering per platform was a mistake, and every time I've touched wxWidgets in the past decade and a half I've regretted it.
FLTK on the other hand is ugly as sin, but I've found it reliable enough to not act in surprising ways, and it's also small enough to where you can vendor it and build it alongside your program.