function createOrGetSecondaryElement(rootDocument) {
  var secondaryElement = secondaryElements.get(rootDocument);

  if (secondaryElement) {
    if (!secondaryElement.parentElement) {
      this.rootDocument.body.appendChild(secondaryElement);
    }

    return secondaryElement;
  }

  var element = rootDocument.createElement('textarea');
  secondaryElements.set(rootDocument, element);
  element.id = 'HandsontableCopyPaste';
  element.className = 'copyPaste';
  element.tabIndex = -1;
  element.autocomplete = 'off';
  element.wrap = 'hard';
  element.value = ' ';
  rootDocument.body.appendChild(element);
  return element;
}
Create and attach newly created focusable element to the DOM.

@return {HTMLElement}