docs: function Tabz(options) {
      var i, el;
  
      options = options || {};
      var root = options.root || document,
          unhook = options.unhook,
          referenceElement = options.referenceElement,
          defaultTabSelector = options.defaultTabSelector || '.default-tab';
  
      if (!unhook) {
          var css;
          /* inject:css */
          /* endinject */
  
          if (!referenceElement) {
              // find first <link> or <style> in <head>
              var headStuff = document.querySelector('head').children;
              for (i = 0; !referenceElement && i < headStuff.length; ++i) {
                  el = headStuff[i];
                  if (el.tagName === 'STYLE' || el.tagName === 'LINK' && el.rel === 'stylesheet') {
                      referenceElement = el;
                  }
              }
          }
          cssInjector(css, 'tabz-css-base', referenceElement);
  
          for (var key in options) {
              if (this[key] === noop) {
                  this[key] = options[key];
              }
          }
  
          /**
           * @summary The context of this tab object.
           * @desc The context may encompass any number of tab panels (`.tabz` elements).
           * @type {HTMLDocumen|HTMLElement}
           */
          this.root = root;
  
          // enable first tab on each tab panel (`.tabz` element)
          forEachEl('.tabz>header:first-of-type,.tabz>section:first-of-type', function(el) {
              el.classList.add('tabz-enable');
          }, root);
  
          // enable default tab and all its parents (must be a tab)
          this.tabTo(root.querySelector('.tabz > header' + defaultTabSelector));
  
          setTimeout(function() {
              forEachEl('.tabz > section', function(el) {
  
                  // Step 1: A bug in older versions of Chrome (like v40) that inserted a break at mark-up location of an absolute positioned block. The work-around is to hide those blocks until after first render; then show them. I don't know why this works but it does. Seems to be durable.
                  el.style.display = 'block';
  
                  // Step 2: Adjust absolute top of each rendered folder to the bottom of its tab
                  el.style.top = el.previousElementSibling.getBoundingClientRect().bottom - el.parentElement.getBoundingClientRect().top + 'px';
  
              }, root);
          }, 0);
      }
  
      var method = unhook ? 'removeEventListener' : 'addEventListener';
      var boundClickHandler = onclick.bind(this);
      forEachEl('.tabz', function(tabBar) {
          tabBar.style.visibility = 'visible';
          tabBar[method]('click', boundClickHandler);
      }, root);
  }