Getting used to TrackIR, but I have noticed that after playing a while, it loses it's X,Y,Z translation. I'll ALT-tab out of the game, bring up the TrackIR display, and check that it IS tracking my head when I move up, down, in, out, or side-to-side. But I can't get this back in the game until I log out/log back in. And then I might lose it again pretty quickly.
But within the TrackIR display, it always shows my head movements correctly.