code: function() {
              this.$container = $(this.options.buttonContainer);
              this.$container.on('show.bs.dropdown', this.options.onDropdownShow);
              this.$container.on('hide.bs.dropdown', this.options.onDropdownHide);
              this.$container.on('shown.bs.dropdown', this.options.onDropdownShown);
              this.$container.on('hidden.bs.dropdown', this.options.onDropdownHidden);
          }
docs: Builds the container of the multiselect.