customdoxygen.css

  pre.fragment
  {
    overflow: visible;
    text-wrap: unrestricted;
    white-space: -moz-pre-wrap; /* Moz */
    white-space: -pre-wrap; /* Opera 4-6 */
    white-space: -o-pre-wrap; /* Opera 7 */
    white-space: pre-wrap; /* CSS3  */
    word-wrap: break-word; /* IE 5.5+ */
  }
}