[Pharo-dev] Fast Table scroll steps

I don't understand the step size of the fast table scroll bar. What does container bottom have to do with delta & pageDelta? recalculateVerticalScrollBar | interval delta pageDelta visibleRows numberOfRows | self hasDataSource ifFalse: [ ^ self ]. self recalculateVerticalScrollBarVisibilityIfHidden: [ ^ self ]. visibleRows := self container calculateExactVisibleRows. numberOfRows := self dataSource numberOfRows. interval := (visibleRows / numberOfRows) asFloat. delta := 1/(self container bottom). pageDelta := (self innerBounds height - 10) / (self container bottom). self verticalScrollBar scrollDelta: delta pageDelta: pageDelta; interval: interval