message: Fixed findScrollableParent for the whole document scrollable
diff: @@ -90,16 +90,13 @@ function isElementVisible(element: HTMLElement, threshold: number = 0) : boolean
  function findScrollableParent(element: HTMLElement): HTMLElement {
  if (!element) {
  - return <any>window;
  + return <any>document.documentElement;
  }
  if (
  element.scrollHeight > element.clientHeight &&
  (getComputedStyle(element).overflowY === "scroll" ||
  getComputedStyle(element).overflowY === "auto")
  ) {
  - if(element === document.body) {
  - return <any>window;
  - }
  return element;
  } else {
  return findScrollableParent(element.parentElement);
  