Yes, that's one of the swings we've taken at this idea. It had some success offering components, but I don't recall ever being able to use it to drive an app very well. I think I tried to drive Office with it back in the late 90s and it was too buggy to use for anything at all. I don't see any reason why in principle it shouldn't work, and maybe there was a point it did, but historically these APIs decay like crazy because they never attain critical mass.