prevent scrolling to the first selected element in multiselect

[delphir-com]

Seems that there is a bug in this action as every click on other that the fist selected element in the list (when auto-close is disabled) scrolls list up to the first selected element again and again.

Possible Solution:
self.highlightFirstItem() must be removed or ignored in case when there are more than 1 item selected.

    container.on('select', function () {
      if (!container.isOpen()) {
        return;
      }

      self.setClasses();
      self.highlightFirstItem();
    });

[jgbishop]

This may be a duplicate of #4417.