the only way to style only the mulitselect dropdown list differently than other dropdown lists is to run a js script to add a css class...

  function setupMultiSelectULStyle (styleName) {
    var selects = $("select");
    $.each(selects, function(index, item) {
      var data = $(item).data("kendoMultiSelect");
      if (data !== undefined && data !== null)
        setupMultiSelectULStyleSingle(data, styleName);
    });
  }

i think if you are creating elements that are not wrapped in parent element style they should have some way to style by parent control type differentiated css selector


<div class="k-list-multiselect k-list-container k-popup ... " id="..." >
<div class="k-list-dropdown  k-list-container k-popup ... " id="..." >