message: PullToRefresh: checking if event cancelable
diff: @@ -53,7 +53,7 @@ function cancelEvent(event: any) {
  while (event.originalEvent) {
  event = event.originalEvent;
  }
  - if (event.preventDefault) {
  + if (event.preventDefault && event.cancelable) {
  event.preventDefault();
  }
  if (event.stopPropagation) {
  