index.js

this.$palettes.on('hidden.bs.collapse', function (e) {
      var $this = $(this),
        $target = $(e.target);

      var $span = $("span[itemprop=expandCollapseIcons]");
      var $i    = $("span[itemprop=expandCollapseIcons] i");

      // It's the $i who has class "icon-chevron-down" so

      if ($i.hasClass('icon-chevron-down')) {
        $i.removeClass('icon-chevron-down').addClass('icon-chevron-up');
      } else {
        $i.removeClass('icon-chevron-up').addClass('icon-chevron-down');
      }


    });

    this.$palettes.on('show.bs.collapse', function (e) {
      var iframe = self.iframe(),
        $iframe = $(iframe.document),
        $this = $(this),
        $target = $(e.target),
        targetPage = $target.attr('id').slice(0, -6),
        $expandCollapseIcons = find('.accordion-toggle span[itemprop="expandCollapseIcons"] i');

      var $span = $("span[itemprop=expandCollapseIcons]");
      var $i    = $("span[itemprop=expandCollapseIcons] i");

      // It's the $i who has class "icon-chevron-down" so

      if ($i.hasClass('icon-chevron-up')) {
        $i.removeClass('icon-chevron-up').addClass('icon-chevron-down');
      } else {
        $i.removeClass('icon-chevron-down').addClass('icon-chevron-up');
      }

      if (targetPage === 'styles')
        return;
      if (iframe.jQuery)
        iframe.jQuery.mobile.changePage('#' + targetPage);
      self.$pageMarker.val(targetPage);
    });
  },