/* shows correct units menu based on data in current window */
_mfunits()
{
        if (_is2d(1))   // all 2D but not XYZ
        {
                _mf("units2d.pan");
        }
        else if (_is3d())   // XYZ
        {
                _MF("unitsxyz.pan");
        }
        else if (_isxy())   // XY
        {
                _MF("serxy.pan");
        }
        else   // series
        {
                _MF("serdata.pan");
        }
}