tab_text (t, 2, 0, TAB_CENTER | TAT_TITLE, _("Contrast"));
tab_text (t, 3, 0, TAB_CENTER | TAT_TITLE, _("Value of Contrast"));
tab_text (t, 2, 0, TAB_CENTER | TAT_TITLE, _("Contrast"));
tab_text (t, 3, 0, TAB_CENTER | TAT_TITLE, _("Value of Contrast"));