protected override bool OnScrollEvent (Gdk.EventScroll evnt)
{
switch (evnt.Direction) {
case ScrollDirection.Up:
TargetValue = Math.Max (TargetValue - Vadjustment.StepIncrement, 0);
break;
case ScrollDirection.Down:
TargetValue = Math.Min (TargetValue + Vadjustment.StepIncrement, Vadjustment.Upper - Vadjustment.PageSize);
break;
default:
return base.OnScrollEvent (evnt);
}
return true;
}