>>106289779
>XP control panel (*.CPL) files
Of course you'd be paying attention to these specific applets - XP's control panel inherited the Web View from ME (which in turn was probably inspired by Neptune's idea of web-based UI, like the ill-fated Activity Centers) and made it default, although it still had the good ol' classic view.
Had an XP SP3 (maybe it's different in the RTM release?) VM ready, unpacked contents of the .cpls in System32 with 7-Zip: only 2 of those built-in applets are proven to be HTA-based in plain sight: appwiz and nusrmgr (fun fact: the applet was initially developed for the Neptune project). Regardless, not related to the DirectUI framework used.
Not that any of that would matter after the Explorer (and thus control panel) rewrite in Vista, as all these integrated control panel applets are basically shell folder-based: rendered by DirectUI-based explorer. None of that HTA bullshit.
>not to mention how MS tries to move all of the settings to the Immersive Settings app, anyways.
Amazed? Rather disappointed. If that's all the evidence you've got of "every version of Windows since XP has written large parts of its UI in actual, textual, interpreted JavaScript.", then the argument seems poor.