@Override
 public String toString() {
   String output = "";
   if (!empty) {
     output +=
         "<html>"
             + "<span style=\"font-size:11px;margin:2px 0 2px 4px;\">"
             +
             // "Match "+number+": <b>'"+match+"'</b>" +
             I18N.getMessage(
                 I18N.getGUIBundle(),
                 "gui.dialog.parameter.regexp.regular_expression.result_list.match",
                 number,
                 "<b>'" + Tools.escapeHTML(match) + "'</b>")
             + "</span>";
     if (groups.length > 0) {
       output += "<ol style=\"margin:1px 0 0 24px\">";
       for (int i = 0; i < groups.length; i++) {
         // output += "<li>Group matches: <b>'" + groups[i] +"'</b></li>";
         output +=
             "<li>"
                 + I18N.getMessage(
                     I18N.getGUIBundle(),
                     "gui.dialog.parameter.regexp.regular_expression.result_list.group_match",
                     "<b>'" + Tools.escapeHTML(groups[i]) + "'</b>")
                 + "</li>";
       }
       output += "</ul>";
     }
     output += "</html>";
   } else {
     output +=
         "<html>"
             + "<span style=\"font-size:11px;margin:2px 0 2px 4px;\">"
             + I18N.getMessage(
                 I18N.getGUIBundle(),
                 "gui.dialog.parameter.regexp.regular_expression.result_list.empty")
             + "</span>";
     output += "</html>";
   }
   return output;
 }