Windows 8 brings up a popup on the first install of an "application that displays web pages" and offers the user the chance to set it as the default. We should dig into this UI and try to understand what triggers it, and whether we can retrigger it under certain circumstances.
Created attachment 629390 [details]
Screenshot of default browser selection window
Gideon mentioned that this should work with the SHOpenWithDialog API. I confirmed just now that it works on Windows 8 with the following code:
info.pcszFile = L"http";
info.pcszClass = NULL;
info.oaifInFlags = OAIF_FORCE_REGISTRATION | OAIF_URL_PROTOCOL | OAIF_REGISTER_EXT;
HRESULT hr = SHOpenWithDialog(NULL, &info);