Well, it's not a matter of not believing you, i always try to take a statement of a 4star forum poster as being dominating about my personal faults. But, while i would love to believe you, this is not a religion thing, and i'm more of a facts-driven type. So, i simply do not see (not by overlooking obvious things, but due to the fact that they aren't there) any entry in any of the setup pages. As i said, adding an entry in the #defines tab, i.e. -DF_CPU=12000000UL, leads to a warning of duplicate definitions, but the #defines tab has been totally empty before i added the above line.
My cbp file is attached below, had to rename it to .txt... I see that the clock setting is describved as being an option, but on the options tab there's nothing as well.
Oooops: just saw that you're a 5star poster! :-)