_LayoutItem
_LayoutItem(previousItem, previousInfo);
_LayoutItem(_SplitterItemAt(index), splitterInfo);
_LayoutItem(nextItem, nextInfo);
_LayoutItem(splitterItem, BRect(xOffset, yOffset,
_LayoutItem(item, BRect(), false);
_LayoutItem(item, BRect(xOffset, yOffset, xOffset + width,
void _LayoutItem(BLayoutItem* item, BRect frame,
void _LayoutItem(BLayoutItem* item,