
Re: "Then why not just use something
" a cross-platform GUI is quite impossible, unless all the relevant players sit at a table and define a standard all of them abide to. Than UI development will evolve at a glacial pace."
I'm actually working on THAT VERY PROBLEM. A low-level X11 + Win32 toolkit with high-level APIs (and a "visual studio '97 like" IDE) that would make it possible to do exactly what you said. X11 'Event' style interface, with Win32 API similarities. high level and low level. Intelligent paint/expose processing. But I've been working on it for YEARS, and still need money to live on. So yeah.
I started coding for OS/2 in the early 90's [took a class]. I switched to Windows 3.x coding because I couldn't purchase OS/2 for myself without buying a PS/2. Windows coding was great until ".Not" and C-pound came along. That's when I switched my focus to Linux and FreeBSD, using FreeBSD as my daily-driver desktop, being truly disappointed and seeing 'embedded' and POSIX as having a better opportunity that windows UI.
GTK also works for cross-platform, worthy of mention. And wxWidgets.
(I only downvoted because you said 'impossible' - nothing is impossible - but some things, of course, are highly unlikely...)