Handling ScrollView.Scrolled event in iOS

I have an XLabs ExtendedScrollView that contains a lot of text plus a little indicator at the bottom to let people know there is more content if they scroll down. I want the indicator to disappear if they scroll and reappear when they are scrolled to the top. My implementation below works fine in Android, but the .Scrolled event never occurs in iOS even when I scroll. Any ideas?

var scrollable = new ExtendedScrollView();
scrollable.Content = content;
scrollable.Scrolled += scrollable_Scrolled;

void scrollable_Scrolled(ScrollView arg1, Rectangle arg2)
        {
            var x = scrollable.Position;
            if (x.Y == 0) theresMore.IsVisible = true;
            else theresMore.IsVisible = false;
}