With one Objects on Path group of two or more objects selected, the
Selection and Objects on Path tools show a square Space widget beyond the
last object, ahead along the path. Dragging it moves the last object
along the path, around its bends, as far as the pointer moves along it,
and the objects between follow evenly while the first one stays. With
Alt (Option on macOS) the objects spread from both ends toward or away
from the center of an open path, or of the first anchor of a closed one.
The distance between the objects shows next to the pointer in the
document's units; the drag is one undo step, and Escape cancels it.
- object.objectsOnPath.options takes spacing (points, or "auto", the
default even spread) and start (points from the first anchor). A
spacing the path has no room for is drawn smaller and kept, so a
longer path brings it back. Older files read as Auto.
- Moving the group, Pivot, Rotate, path edits, copies and saving keep
the Space. Scaling, rotating or shearing the group keeps the first
and last objects where the transform takes them on the new path, live
shapes included; a value that cannot be kept that way scales with the
path's length.
- The Rotate All widget follows the first object when Space moves it.
Behavior: https://helpx.adobe.com/illustrator/desktop/manage-objects/arrange-objects/rearrange-and-edit-objects-on-a-path.html
and https://helpx.adobe.com/illustrator/using/objects-on-path.html.
Double-clicking the Objects on Path tool opens Objects on Path Tool
Options: a nine-point Pivot grid, a Rotate field, Reset (the center and
0) and Save. Save sets the tool's options, which last across tool
switches and are saved with the preferences. The tool sends them with
each attach, and object.objectsOnPath.attach without pivot or rotate
uses them, so they apply to the objects attached next; groups attached
before keep theirs.