Hi Dinony,
We experience poor scrolling performance in IE even if we set vsDebounceTime to a large value. After some investigation we have discovered that Angular change detection is triggered on each 'scroll' event despite debounceTime(). This can be prevented by wrapping Observable.fromEvent(..., 'scroll') in zone.runOutsideAngular().
I couldn't figure out how to create a cold observable with Observable.fromEvent as if subscribe() is called outside of zone.runOutsideAngular() Angular change detection is still triggered on each scroll event. The proposed solution adds an intermediate scroll$ Subject.
Kind regards,
Serguei.

This reverts commit 91b5a6b.