I’m using the IWebBrowser2 interface to IE9 in a standard Win32 app. Pages with controls like buttons are rendered without theming, so look like something from the Windows 2000 era. The identical page displays correctly using the stand-alone IE9. All pages have
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
in the header
Any thoughts?

You must implement
IDocHostUIHandler, then in the methodGetHostInfoappend theDOCHOSTUIFLAG_THEMEto thedwFlags: