preferredHighlightBegin and preferredHighlightEnd do not work as expected

When I scroll down my listview and the last visible item is selected, I cannot see the bottom border of the rectangle of the selected item.
If I define:
preferredHighlightBegin: 0
preferredHighlightEnd: height
highlightRangeMode: "ApplyRange"
everything work well. So there is maybe a fix to do in the default behavior.

Second issue(see attached file): I want to see always one more item below the selected item, so if I define
preferredHighlightBegin: delegateHeight
preferredHighlightEnd: height - delegateHeight
highlightRangeMode: "ApplyRange"

When I move with arrows from the last item to the second last item, the list is scrolling from one pixel which is strange but the list should not scroll because the listview is already at the bottom of the list.