@takao @alyx @deadheat @coldacid @coolboymew WON menu style is very inconsistent. It's overall a Win32 thing, just running in parallel with the game engine. Looks a bit different from version to version too. The fancy buttons are just Photoshop preset. I actually reimplemented this preset with imagemagick but scratched it and rewrote the effect with my text renderer. Didn't finished it though.
What they did with Steam release is ported everything to their own toolkit actually made for Source. So every Valve product from GoldSource games, to Source and Steam used the same proprietary toolkit. (Steam also shares more code with Source even to this day, maybe even have some Quake I code)
It's very sad it's proprietary because it could be nice C++ game UI toolkit without "immediate mode" crap, although a bit boring visually.
Sorry, nobody needed that info, just too personal... %)
@alyx @coolboymew hey, I loved that UI, but it's still honestly almost as bad as Motif