SceneGroupSelectionTask

construct.scene.group_selection — put the selected items in a new group, as one undo step (scene-tree-ux-v3 §STG-O-3).

In the namespace construct::opal. Declared in src/libs/libconstruct/construct/opal/SceneGroupSelectionTask.hpp.

Detailed description

construct-operations planned this Tier 2 composite and never built it. A model could emulate it with one item.add and N item.set_parent calls: N+1 steps, N+1 approval prompts and N+1 chances to leave the tree half restructured, which vetStructure() then rightly reports as broken part way through. Here the whole change is one coalesced undo step.

The items are the selection, or `itemIds` when given, reduced to the top-most ones (§CEI-D6): a selected parent carries its selected child along, so the child is not moved twice. The group takes the place of the first item when every item shares one parent, and lands at the root otherwise. The new group is selected afterwards.

Not component.nest: that makes a reusable definition, a heavier commitment than putting four items in a group.