Direct Selection: a further Alt-click adds the path's group, then the next group up

Squashed from #4381 onto main.

docs/target-app-parity.md

@@ -681,6 +681,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
     `path.reshapeSegment`, `object.blend.spine.reshapeSegment`, `path.convertAnchor`, `path.curvatureEdit`, `path.insertAnchor`, `path.moveAnchors`, `path.reshape`, `path.close` and the Pencil, Curvature, Knife, Eraser, Path Eraser, Smooth, Join and Blob Brush commands refuse a number, point or handle given as text, such as "10", and leave the document unchanged; `path.convertAnchor` refuses an `x` without a `y`, or a `y` without an `x`.
     `path.close` and `path.setHandle` (`independent`), `path.moveAnchors` (`patterns`), the Pencil (`closed`, `keepSelected`, `fill`), Curvature (`closed` and a point's `corner`), `path.curvatureEdit` (`corner`), `path.reshapeSegment` (`perpendicular`) and the Blob Brush (`keepSelected`, `mergeOnlySelection`, `merge`) refuse a value other than true, false or null, such as "true", and leave the document unchanged.
   - **Group Selection (#2441):** a click picks one path of a compound path (its outline within the pick tolerance, else the innermost path whose area holds the click: the outer shape or a hole), Shift-click adds another, and a click on a selected path adds the compound path, as a click on a group member climbs to its group. A path selected this way moves, rotates and scales on its own; paint still goes to the compound path.
+    With Direct Selection, an Alt-click on a path selected whole adds its group, and each further Alt-click adds the next group up, as Group Selection's clicks do; the climb stops below the layer and its sublayers and at the isolated object. An Alt-drag still copies the selection, and Alt+Shift-click on a segment or the fill still adds or removes the path. Public references: [Select objects](https://web.archive.org/web/20250904012025/https://helpx.adobe.com/illustrator/using/selecting-objects.html) and [Default keyboard shortcuts](https://web.archive.org/web/20260726060015/https://helpx.adobe.com/illustrator/using/default-keyboard-shortcuts.html) (archived copies).
     With Direct Selection, Shift pressed during the drag of a curved segment keeps both of its handles at right angles to the line between its anchors, on the same side and at the same length (`path.reshapeSegment {perpendicular}`). Shift held while any segment is dragged with the Anchor Point tool or the Pen with Alt does the same. With the Anchor Point tool, Shift held at the press on an anchor (or a selected blend's spine point) moves it, handles and all, instead of pulling out handles; Shift kept down keeps the move at 45° steps, and a Shift-click that doesn't move leaves the anchor as it was (`path.moveAnchor`). A selected blend spine's segment dragged with the Anchor Point tool, or a curved one dragged with Direct Selection, bends the same way (`object.blend.spine.reshapeSegment`).
   - **Live Corners:** drag a live rectangle's corner widgets (Selection or Direct Selection) to round all corners, with a radius readout; with Direct Selection, select corner anchors to show and round just those corners (#381). Each corner keeps its own radius and kind (Round, Inverted Round, Chamfer): Alt-click a widget to cycle the kind, double-click it for the Corners dialog, and the Properties and Transform radius fields set the selected corners (`object.setLiveShape {corners, radius, kind}`). A link toggle behind Corner Radius (the `singleCornerRadius` preference) switches the panels to a field for each corner of a live rectangle: Top Left, Top Right, Bottom Right and Bottom Left. Corners stay circular when the rectangle is scaled unevenly or along its own sides when rotated (the radius keeps its size, or scales by the mean scale with Scale Corners on); only a shear distorts them. On a rectangle that isn't square every corner is the same circle: a radius past half the shorter side stops there for all of them, the widgets sit on the corners as drawn and turn the edited corners red at that limit, CSS export writes the drawn radii, and rectangles saved stretched by older versions get circular corners when their corners are next set (#442). Live Corners work on any path's corners too, as on a rectangle's (#511): a star's, a live polygon's (which also shows them to the Selection tool, has a Corner Radius field in the Properties and Transform panels and keeps its radius as its sides change) and a pen path's, wherever two sides meet at an angle at an anchor that isn't smooth: curved sides too, trimmed to what the cut leaves of them (#1144). Direct Selection shows the widgets of every corner, or of the corners holding selected anchors; each corner is a circle tangent to both sides, drawn no larger than takes its cut halfway along its shorter side; a path keeps its uncut outline so its corners stay editable, and the same command, dialog, angle preference and View › Hide Corner Widget apply. With Direct Selection a click on a widget (no drag) selects its corner, as a click on the corner's anchor does, so the next drag on it rounds that corner alone; Shift-click toggles it (#1239). While a corner widget is dragged with the Selection tool the bounding box hides, so the rounding shows against the path alone (#1229). A round corner next to a curved side curves smoothly instead of sticking out of the shape (#1547, fixes #1512).
     View › Hide Edges hides the Live Corners widgets, the bounding box and the type widget, and the selection tools then do not answer a press on them or change the cursor over them.