XCEngine/docs/plan/NewEditor_TreeResidualDuplicationClosurePlan_2026-04-22.md

NewEditor Tree Residual Duplication Closure Plan

Date: 2026-04-22 Status: In Progress

Goal

• Close the true remaining duplication between HierarchyPanel and the project left tree after the TreePanelHost / UIEditorTreePanelBehavior cleanup.
• Keep the solution rooted in existing modules instead of creating new Behavior / Host / Support files.
• Reduce code only where the duplication is structurally real, not where product semantics differ.

Why A New Plan Is Needed

• The previous plan completed the removal of the tree glue layer.
• That did not automatically mean the hierarchy tree and project tree were free of all true duplication.
• The remaining work is smaller in scope, but it is real and should be tracked separately instead of being hidden under the completed root plan.

Confirmed Residual Duplication

1. Hosted panel command focus claiming is still duplicated

Current duplicated shape:

• HierarchyPanel::ClaimCommandFocus(...)
• ProjectPanel::ClaimCommandFocus(...)
• InspectorPanel::ClaimCommandFocus(...)

This is app-layer hosted panel behavior, not tree-business behavior.

2. Tree rename host skeleton is still partially duplicated

Current duplicated shape:

• ClearRenameState(...)
• QueueRenameSession(...)
• TryStartQueuedRenameSession(...)
• UpdateRenameSession(...)

Notes:

• HierarchyPanel has a single tree surface.
• ProjectPanel has both tree and grid rename surfaces.
• The commit side-effects must stay local, but the session host skeleton still contains real duplication.

3. Tree append/update skeleton must be re-audited carefully

• Some call order is shared: tree background, tree foreground, inline rename overlay, drop preview.
• But ProjectPanel also owns splitter, breadcrumb, grid, context menu, asset drag/drop, and dual-surface rename.
• This area must not be “abstracted for symmetry” unless the extracted part is truly stable and reduces code clearly.

Explicit Non-Goals

• Do not merge panel refresh loops.
• Do not merge project tree and asset grid logic.
• Do not move project or scene runtime semantics into XCEditor.
• Do not create any new Behavior, Host, Helper, Support, or similar glue files.
• Do not refactor for visual symmetry when code ownership would become less clear.

Execution Plan

Phase A. Hosted Panel Command Focus Dedup

Status: Completed

Target:

• Consolidate hosted-panel command focus claiming into an existing app-level module.

Rules:

• No new file.
• Prefer extending an existing app-level focus module.
• Update HierarchyPanel, ProjectPanel, and InspectorPanel together if they share the same pattern.

Validation:

• Build XCUIEditorApp
• Smoke test XCUIEditor.exe

Completed result:

• Consolidated hosted panel command focus claiming into EditorCommandFocusService.h
• Removed duplicated ClaimCommandFocus(...) implementations from HierarchyPanel, ProjectPanel, and InspectorPanel
• Verified by build and smoke test

Phase B. Tree Rename Host Skeleton Dedup

Status: Pending

Target:

• Reduce duplicated tree rename session host code while preserving local business commit behavior.

Rules:

• No new glue layer.
• Keep tree-generic session mechanics in existing tree/editor modules.
• Keep ProjectPanel grid rename semantics local.
• Keep HierarchyPanel scene rename commit local.

Validation:

• Build XCUIEditorApp
• Smoke test XCUIEditor.exe
• Confirm hierarchy rename and project tree/grid rename still start and shut down correctly

Phase C. Final Re-Audit Of Tree Skeleton Duplication

Status: Pending

Target:

• Re-check whether any remaining shared tree call sequence should still be extracted.

Rules:

• Only extract if it removes clear structural duplication.
• If the remaining overlap is just normal orchestration around different business surfaces, record it as intentional and stop.

Validation:

• rg verification of targeted duplicate blocks
• Build XCUIEditorApp
• Smoke test XCUIEditor.exe

Acceptance

• Previous root plan is archived.
• Remaining true duplication is tracked separately.
• Hosted panel command focus duplicate is removed from the duplicated panels.
• Tree rename host skeleton duplication is reduced without breaking project grid/tree split semantics.
• No new glue-layer file is introduced.
• XCUIEditorApp builds and smoke tests pass after each completed phase.