Hi Joe,
Nope, that's not what I'm saying. I was just making sure what area of the tabcontrol we are talking about. But, as you stated the exact property as tabPage1.BackColor, there is no misunderstanding any more.
I tested changing tabPage1.BackColor to WhiteSmoke and it works fine on 6.4.0Beta1b (can't test on Beta1c right now).
Please make sure no caching is involved, like uppering privateversion etc.
Palli