Stock futures dragged lower Tuesday as the dollar hovered in mixed territory and overseas markets were generally quiet. Dow futures hung 24.2 points below fair market value. S&P 500 futures were off 3.5 points, and Nasdaq 100 futures were down 3.9 points. Small caps lagged, with Russell 2000 futures down 5.6 points. That index slipped 1.8% on Monday.