Hinzufgen in template/css/jquery.sumoselect.css:

.SumoSelect.open > .search > label, .SumoSelect.open > .search > span {
  visibility:hidden;
}
.SumoSelect .search-txt {
  display:none;
  outline:0;
}
.SumoSelect.open .search-txt {
  display: inline-block;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  margin: 0;
  padding: 5px 8px;
  border: none;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  border-radius: 5px;
}

Anpassen template/javascript/extra/sumoselect.js.php

$('select:not([name=country])').SumoSelect();
$('select[name=country]').SumoSelect({search:true});
