code: function (selector) {
              return function () {
                  return this.then(function () {
                      // if "Expand all" is visible then
                      if (this.visible(selector + ' .cms-dragbar-expand-all')) {
                          this.click(selector + ' .cms-dragbar-expand-all');
                      } else if (this.visible(selector + ' .cms-dragbar-collapse-all')) {
                          // if not visible, then first "Collapse all"
                          this.click(selector + ' .cms-dragbar-collapse-all');
                          this.wait(100);
                          this.click(selector + ' .cms-dragbar-expand-all');
                      } else {
                          throw new Error('Given placeholder has no plugins');
                      }
                  });
              };
          }
docs: Expands all plugins in the given placeholder.
  
  @function expandPlaceholderPlugins
  @param {String} selector placeholder selector
  @returns {Function}