Earlier quoted context omitted.
> The problem is that Gtk is ugly, Qt is extremely bloated and WxWidgets barely works. Seems like the author didn't look at cross-platform toolkits since 90s.
Honestly, this is a guy who uses GDI, so most of the above options will feel bloated already when looking at the source tarball sizes. That said, has there been any fundamentally groundbreaking crossplatform classic UI toolkits released since the 90s? (IMGui is the only one that has seemed interesting but that's specialized and not a general one really)
EDIT: Another commenter suggest only office as example. IIRC, they are building it using chromium as front-end and .NET as backend.