Unfortunately that's not MS-specific. The revered Google used to have the same no-go warning for users of Adwords with Opera. I tried it again just now, the war

Unfortunately that's not MS-specific. The revered Google used to have the same no-go warning for users of Adwords with Opera. I tried it again just now, the warning is gone, but the Adwords interface doesn't load properly (more specifically the dashboard loads, however campaign editor and "Opportunities", whatever that is, don't). I can't imagine how this is not deliberate.