Underlining style for anchors. Can be any of the following:

XmNO_LINE /* no underlines */
XmSINGLE_LINE /* a single, solid, underline */
XmDOUBLE_LINE /* a double, solid, underline */
XmSINGLE_DASHED_LINE /* a single, dashed, underline */
XmDOUBLE_DASHED_LINE /* a double, dashed, underline */

This resource is only honored when the XmNanchorButtons resource is set to False

XmNO_LINE	/* no underlines */
XmSINGLE_LINE	/* a single, solid, underline */
XmDOUBLE_LINE	/* a double, solid, underline */
XmSINGLE_DASHED_LINE	/* a single, dashed, underline */
XmDOUBLE_DASHED_LINE	/* a double, dashed, underline */