I noticed that in Xcode 27 Beta 1 on macOS 27 Beta 1, changing the selection of the segmented control used to switch between the Sidebar and Inspector tabs is animated.
However, the standard segmented controls used by NSTabView/NSTabViewController, as well as a regular NSSegmentedControl, do not appear to have any such animation on macOS 27.
I also tried using the animator proxy:
segmentedControl.animator().selectedSegment = index
but this did not change the behavior.
How can I implement the same kind of segmented control selection animation that Xcode uses? Is there a public API for this, or is it achieved through a different mechanism?
I found the answer myself and was able to resolve this.
It turns out this was actually introduced as a new feature/API in macOS 27, and I had simply overlooked it. The animation can be enabled by assigning one of the new NSSegmentedControl.Role values.
Since I’ve already solved the issue, no further replies are necessary.