Does a WPF menu (and WPF-based apps in general) integrate with the systemwide conventions and settings for things like keyboard shortcuts, default font, etc? Is it a first-class UI toolkit for the system? My impression was it is supposed to be, in a way GTA's UI (or Swing) is not.

About as well as swing ever did, no where near as good as Qt does, I think we'd all agree qt is not the native UI of windows.

Then again, it is hard to judge. Not a lot of win32 apps seem to follow system wide settings either, even the MS ones.

Really? It's just not the impression I get, granted it's been a while since I've used Windows for anything other than to, well, play a bit of GTA. I remember paint.net being a thing (seems it's still around) and it looked and behaved like a Windows app. Qt apps look instantly recognizable and fugly to me on any platform. It's hard to believe that WPF apps had or still have, say, the font-rendering problems Swing apps had or were missing access to affordances like control over the tray icon, etc.

The reason I'm skeptical is that WPF was very much intended to be a first-class Windows-specific ui toolkit. You're telling me it's worse than cross-platform toolkits with all of their necessary design and implementation compromises.

Edit: Oh! I figured out where I was confused. WPF and Winforms. Not the same thing.

DirectX is at the same level of abstraction as Win32's Graphic Device Interface (GDI) and Hardware Abstraction Layer (HAL) that the rest of Win32's "native toolkit" was built on top of; Windows.UI is just as "native" as Win32 ever was. It should not be a surprise that the hardware abstraction toolkit beat into performance submission by performance demanding games is the new native layer for Windows. The surprise should be how long it has taken to make the transition across. (Avalon promised it back in Vista and WPF was the closest to delivering it. Windows 8 finally delivered on the Avalon promise.)

Examples: My Summer Car, Sol 0, Software Inc.