A split view manages the dividers and orientation for a split view controller (an instance of the
NSSplitViewController class.) By default, dividers are oriented horizontally so that sibling views are arranged vertically, from top to bottom, in the containing split view controller.
- macOS 10.10+
Divider indices are zero-based, with the leftmost or topmost divider (depending on the value of the
isVertical property) having an index of