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+# D.2b inventory container-switching — Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Click a side bag in the inventory pack-selector → the grid shows that bag's contents (opened via a `Use 0x0036` → `ViewContents 0x0196` full-replace round-trip), the open bag shows the retail triangle, the selected cell shows the retail green/yellow square; click the main-pack cell → back.
+
+**Architecture:** Add an authoritative full-replace path to the Core object table (`ReplaceContents`), reroute the `ViewContents` wiring through it, add a thin `WorldSession.SendUse` wire wrapper, give `UiItemSlot` two procedural indicator overlays (modeled on the existing DragAccept overlay), and give `InventoryController` `_openContainer`/`_selectedItem` state with per-cell click roles (grid→select, container→open+select). `GameWindow` injects the two send callbacks.
+
+**Tech Stack:** C# .NET 10, xUnit. Layers: `AcDream.Core` (object table), `AcDream.Core.Net` (wire + wiring), `AcDream.App` (UI widgets + controller + window).
+
+**Spec:** `docs/superpowers/specs/2026-06-22-d2b-container-switching-design.md`. Decomp anchors: `UpdateOpenContainerIndicator 0x004e3070`/`SetOpenContainerState 0x004e1200` (triangle `0x06005D9C`); `ItemList_SetSelectedItem 0x004e2fe0`/`SetSelectedState 0x004e1240` (square `0x06004D21`). Wire: ACE `GameEventViewContents.cs` (entries `OrderBy(PlacementPosition)`, no slot field → `ContainerSlot = index`).
+
+**Build/test commands** (run from repo root `C:\Users\erikn\source\repos\acdream\.claude\worktrees\hopeful-maxwell-214a12`):
+- One project's tests: `dotnet test tests/AcDream.Core.Tests/AcDream.Core.Tests.csproj`
+- Full suite at the phase boundary: `dotnet test`
+
+---
+
+## Task 1: `ClientObjectTable.ReplaceContents` (full-replace membership)
+
+**Files:**
+- Modify: `src/AcDream.Core/Items/ClientObjectTable.cs` (add a method after `GetContents`, ~line 316)
+- Test: `tests/AcDream.Core.Tests/Items/ClientObjectTableTests.cs` (add after `GetContents_UnknownContainer_Empty`)
+
+- [ ] **Step 1: Write the failing tests**
+
+Add to `ClientObjectTableTests.cs`:
+
+```csharp
+[Fact]
+public void ReplaceContents_RecordsAllInListOrder()
+{
+ var table = new ClientObjectTable();
+ table.ReplaceContents(0xC9u, new uint[] { 0xA01u, 0xA02u, 0xA03u });
+ Assert.Equal(new[] { 0xA01u, 0xA02u, 0xA03u }, table.GetContents(0xC9u));
+ Assert.Equal(0xC9u, table.Get(0xA01u)!.ContainerId);
+}
+
+[Fact]
+public void ReplaceContents_SecondSmallerList_DetachesDropped() // the full-REPLACE semantics (vs the old additive merge)
+{
+ var table = new ClientObjectTable();
+ table.ReplaceContents(0xC9u, new uint[] { 0xA01u, 0xA02u, 0xA03u });
+ table.ReplaceContents(0xC9u, new uint[] { 0xA02u }); // A01 + A03 removed server-side
+ Assert.Equal(new[] { 0xA02u }, table.GetContents(0xC9u));
+ Assert.Equal(0u, table.Get(0xA01u)!.ContainerId); // detached, not lingering
+ Assert.Equal(0u, table.Get(0xA03u)!.ContainerId);
+ Assert.Equal(0xC9u, table.Get(0xA02u)!.ContainerId);
+}
+
+[Fact]
+public void ReplaceContents_ReordersToNewListOrder()
+{
+ var table = new ClientObjectTable();
+ table.ReplaceContents(0xC9u, new uint[] { 0xA01u, 0xA02u });
+ table.ReplaceContents(0xC9u, new uint[] { 0xA02u, 0xA01u });
+ Assert.Equal(new[] { 0xA02u, 0xA01u }, table.GetContents(0xC9u));
+}
+
+[Fact]
+public void ReplaceContents_ZeroContainer_NoOp()
+{
+ var table = new ClientObjectTable();
+ table.ReplaceContents(0u, new uint[] { 0xA01u });
+ Assert.Empty(table.GetContents(0u));
+ Assert.Null(table.Get(0xA01u));
+}
+```
+
+- [ ] **Step 2: Run the tests to verify they fail**
+
+Run: `dotnet test tests/AcDream.Core.Tests/AcDream.Core.Tests.csproj --filter "FullyQualifiedName~ReplaceContents"`
+Expected: FAIL — `'ClientObjectTable' does not contain a definition for 'ReplaceContents'` (compile error).
+
+- [ ] **Step 3: Implement `ReplaceContents`**
+
+In `ClientObjectTable.cs`, immediately after the `GetContents` method (~line 316), add:
+
+```csharp
+ ///
+ /// Replace a container's entire membership with (in order) — the
+ /// authoritative full snapshot the server sends in ViewContents (0x0196) when you open a
+ /// container. Members no longer present are detached (ContainerId → 0); new members are
+ /// recorded with ContainerSlot = list index. ACE writes ViewContents entries
+ /// OrderBy(PlacementPosition) with NO explicit slot field (GameEventViewContents.cs), so the
+ /// list order IS the slot order. Fires ObjectAdded/ObjectMoved so bound UI repaints.
+ /// Retail consumer: ClientUISystem::OnViewContents.
+ ///
+ public void ReplaceContents(uint containerId, IReadOnlyList guids)
+ {
+ ArgumentNullException.ThrowIfNull(guids);
+ if (containerId == 0) return;
+
+ var keep = new HashSet(guids);
+
+ // Detach prior members no longer present (they left the container server-side). GetContents
+ // returns a snapshot, so mutating the index inside the loop is safe.
+ foreach (var old in GetContents(containerId))
+ {
+ if (keep.Contains(old)) continue;
+ if (!_objects.TryGetValue(old, out var o) || o.ContainerId != containerId) continue;
+ o.ContainerId = 0;
+ Reindex(o, containerId);
+ ObjectMoved?.Invoke(o, containerId, 0);
+ }
+
+ // Record new members in order; ContainerSlot = index reconstructs the server PlacementPosition.
+ for (int i = 0; i < guids.Count; i++)
+ {
+ uint g = guids[i];
+ bool existed = _objects.TryGetValue(g, out var obj);
+ if (!existed || obj is null)
+ {
+ obj = new ClientObject { ObjectId = g };
+ _objects[g] = obj;
+ }
+ uint oldContainer = obj.ContainerId;
+ obj.ContainerId = containerId;
+ obj.ContainerSlot = i;
+ Reindex(obj, oldContainer);
+ if (!existed) ObjectAdded?.Invoke(obj);
+ else ObjectMoved?.Invoke(obj, oldContainer, containerId);
+ }
+ }
+```
+
+- [ ] **Step 4: Run the tests to verify they pass**
+
+Run: `dotnet test tests/AcDream.Core.Tests/AcDream.Core.Tests.csproj --filter "FullyQualifiedName~ReplaceContents"`
+Expected: PASS (4 tests).
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add src/AcDream.Core/Items/ClientObjectTable.cs tests/AcDream.Core.Tests/Items/ClientObjectTableTests.cs
+git commit -m "feat(D.2b): ClientObjectTable.ReplaceContents — authoritative full-replace for ViewContents
+
+Co-Authored-By: Claude Opus 4.8 (1M context) "
+```
+
+---
+
+## Task 2: route `ViewContents` wiring through `ReplaceContents`
+
+**Files:**
+- Modify: `src/AcDream.Core.Net/GameEventWiring.cs:253-266` (the ViewContents handler)
+- Test: `tests/AcDream.Core.Net.Tests/GameEventWiringTests.cs` (add after `WireAll_ViewContents_RecordsMembershipInClientObjectTable`)
+
+- [ ] **Step 1: Write the failing test**
+
+Add to `GameEventWiringTests.cs` (the existing `WireAll_ViewContents_RecordsMembershipInClientObjectTable` stays — it still passes under replace):
+
+```csharp
+[Fact]
+public void WireAll_ViewContents_IsFullReplace_DropsRemovedItems()
+{
+ var (d, items, _, _, _) = MakeAll();
+
+ // First view of container 0xC9: two items.
+ DispatchViewContents(d, 0x500000C9u, new uint[] { 0x50000A01u, 0x50000A02u });
+ Assert.Equal(2, items.GetContents(0x500000C9u).Count);
+
+ // Second view: only one item — the other was removed server-side. Additive merge would keep both.
+ DispatchViewContents(d, 0x500000C9u, new uint[] { 0x50000A02u });
+ Assert.Equal(new[] { 0x50000A02u }, items.GetContents(0x500000C9u));
+ Assert.Equal(0u, items.Get(0x50000A01u)!.ContainerId);
+}
+
+private static void DispatchViewContents(GameEventDispatcher d, uint containerGuid, uint[] itemGuids)
+{
+ byte[] payload = new byte[8 + itemGuids.Length * 8];
+ BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(0), containerGuid);
+ BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(4), (uint)itemGuids.Length);
+ for (int i = 0; i < itemGuids.Length; i++)
+ {
+ BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(8 + i * 8), itemGuids[i]);
+ BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(12 + i * 8), 0u); // containerType
+ }
+ var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.ViewContents, payload));
+ d.Dispatch(env!.Value);
+}
+```
+
+- [ ] **Step 2: Run the test to verify it fails**
+
+Run: `dotnet test tests/AcDream.Core.Net.Tests/AcDream.Core.Net.Tests.csproj --filter "FullyQualifiedName~ViewContents"`
+Expected: FAIL — `WireAll_ViewContents_IsFullReplace_DropsRemovedItems` asserts `GetContents` has 1 entry, but the current additive `RecordMembership` loop leaves both (count 2) and `0x50000A01` keeps `ContainerId == 0xC9`.
+
+- [ ] **Step 3: Replace the handler body**
+
+In `GameEventWiring.cs`, replace the block at `:253-266` (the comment + handler) with:
+
+```csharp
+ // ViewContents (0x0196) — the server's AUTHORITATIVE full contents list for a container you
+ // opened (Use 0x0036). Treat it as a full REPLACE: flush the container's prior membership and
+ // record the new entries in order (ContainerSlot = index — ACE writes entries
+ // OrderBy(PlacementPosition) with no slot field). The container-open UI (InventoryController)
+ // repaints the grid off the resulting ObjectAdded/Moved events. Retail: ClientUISystem::OnViewContents.
+ dispatcher.Register(GameEventType.ViewContents, e =>
+ {
+ var p = GameEvents.ParseViewContents(e.Payload.Span);
+ if (p is null) return;
+ var guids = new uint[p.Value.Items.Count];
+ for (int i = 0; i < guids.Length; i++) guids[i] = p.Value.Items[i].Guid;
+ items.ReplaceContents(p.Value.ContainerGuid, guids);
+ });
+```
+
+- [ ] **Step 4: Run the test to verify it passes**
+
+Run: `dotnet test tests/AcDream.Core.Net.Tests/AcDream.Core.Net.Tests.csproj --filter "FullyQualifiedName~ViewContents"`
+Expected: PASS (both the existing membership test and the new full-replace test).
+
+- [ ] **Step 5: Commit**
+
+```bash
+git add src/AcDream.Core.Net/GameEventWiring.cs tests/AcDream.Core.Net.Tests/GameEventWiringTests.cs
+git commit -m "feat(D.2b): ViewContents wiring is a full REPLACE (consumes the GameEventWiring TODO)
+
+Co-Authored-By: Claude Opus 4.8 (1M context) "
+```
+
+---
+
+## Task 3: `WorldSession.SendUse` (thin wire wrapper)
+
+**Files:**
+- Modify: `src/AcDream.Core.Net/WorldSession.cs` (add after `SendNoLongerViewingContents`, ~line 1216)
+
+**Test note:** no new unit test. The wire contract (`Use 0x0036` + target guid) is already locked by `tests/AcDream.Core.Net.Tests/Messages/InteractRequestsTests.cs::BuildUse_WritesOpcode0x0036AndTarget`. `SendUse` is a trivial pass-through that mirrors the adjacent, test-free wrappers (`SendNoLongerViewingContents`, `SendDropItem`, `SendAddShortcut`) — there is no send-capture seam on `WorldSession` to assert against, and the round-trip is confirmed at the WireMCP visual gate (Task 8).
+
+- [ ] **Step 1: Add the wrapper**
+
+In `WorldSession.cs`, directly after `SendNoLongerViewingContents` (~line 1216), add:
+
+```csharp
+ /// Send Use (0x0036) — open/use an object by guid (e.g. open a container in your
+ /// inventory). A direct wire send: opening a pack you already hold needs no autowalk, unlike
+ /// GameWindow.SendUse (the world-interaction path). Retail: CM_Physics::Event_Use.
+ public void SendUse(uint targetGuid)
+ {
+ uint seq = NextGameActionSequence();
+ SendGameAction(InteractRequests.BuildUse(seq, targetGuid));
+ }
+```
+
+(`InteractRequests` is in `AcDream.Core.Net.Messages`; confirm the `using AcDream.Core.Net.Messages;` is present at the top of `WorldSession.cs` — it is, used by the other Send wrappers.)
+
+- [ ] **Step 2: Verify it compiles**
+
+Run: `dotnet build src/AcDream.Core.Net/AcDream.Core.Net.csproj`
+Expected: Build succeeded.
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add src/AcDream.Core.Net/WorldSession.cs
+git commit -m "feat(D.2b): WorldSession.SendUse — thin Use 0x0036 wire wrapper for container-open
+
+Co-Authored-By: Claude Opus 4.8 (1M context) "
+```
+
+---
+
+## Task 4: `UiItemSlot` indicator overlays (triangle + square)
+
+**Files:**
+- Modify: `src/AcDream.App/UI/UiItemSlot.cs` (add properties near `DragAcceptSprite` ~line 36; add draw in `OnDraw` ~line 226)
+- Test: `tests/AcDream.App.Tests/UI/UiItemSlotTests.cs` (add after the DefaultEmptySprite test)
+
+- [ ] **Step 1: Write the failing tests**
+
+Add to `UiItemSlotTests.cs`:
+
+```csharp
+// ── Container-switching indicator overlays (decomp SetOpenContainerState 0x004e1200 /
+// SetSelectedState 0x004e1240) ───────────────────────────────────────────────────────
+[Fact]
+public void Selected_defaultsFalse() => Assert.False(new UiItemSlot().Selected);
+
+[Fact]
+public void IsOpenContainer_defaultsFalse() => Assert.False(new UiItemSlot().IsOpenContainer);
+
+[Fact]
+public void SelectedSprite_default_isGreenYellowSquare()
+ => Assert.Equal(0x06004D21u, new UiItemSlot().SelectedSprite);
+
+[Fact]
+public void OpenContainerSprite_default_isTriangle()
+ => Assert.Equal(0x06005D9Cu, new UiItemSlot().OpenContainerSprite);
+```
+
+- [ ] **Step 2: Run the tests to verify they fail**
+
+Run: `dotnet test tests/AcDream.App.Tests/AcDream.App.Tests.csproj --filter "FullyQualifiedName~UiItemSlotTests"`
+Expected: FAIL — `'UiItemSlot' does not contain a definition for 'Selected'` (compile error).
+
+- [ ] **Step 3: Add the properties**
+
+In `UiItemSlot.cs`, after the `DragRejectSprite` property (~line 39), add:
+
+```csharp
+ /// True when this cell is the OPEN container (its contents fill the grid). Draws the
+ /// open-container triangle. Port of UIElement_ItemList::UpdateOpenContainerIndicator
+ /// (0x004e3070) → SetOpenContainerState (0x004e1200): shown when item.itemID == openContainerId.
+ public bool IsOpenContainer { get; set; }
+ /// Open-container triangle sprite (element 0x10000450 on the container prototype
+ /// 0x1000033F). Configurable; guard id != 0 before resolving.
+ public uint OpenContainerSprite { get; set; } = 0x06005D9Cu;
+
+ /// True when this cell is the SELECTED item. Draws the green/yellow selection square.
+ /// Port of UIElement_ItemList::ItemList_SetSelectedItem (0x004e2fe0) → SetSelectedState
+ /// (0x004e1240): shown when item.itemID == selectedItemId. Uniform across item + container cells.
+ public bool Selected { get; set; }
+ /// Selected-item square sprite (element 0x10000342 on the 32×32 item prototype
+ /// 0x10000341; pixel-confirmed green/yellow frame). Drawn as a procedural overlay so it renders
+ /// on the 36×36 container cell too (whose prototype lacks the square child).
+ public uint SelectedSprite { get; set; } = 0x06004D21u;
+```
+
+- [ ] **Step 4: Add the draw calls**
+
+In `UiItemSlot.cs` `OnDraw`, immediately BEFORE the drag-rollover block (the `if (_dragAccept != DragAcceptState.None …`, ~line 226), add:
+
+```csharp
+ // Open-container triangle (retail SetOpenContainerState 0x004e1200) + selected-item square
+ // (retail SetSelectedState 0x004e1240). Drawn procedurally like the digit/drag overlays;
+ // guard id != 0 BEFORE resolving (feedback_ui_resolve_zero_magenta). Triangle under the
+ // square; both under the transient drag overlay below.
+ if (IsOpenContainer && SpriteResolve is not null && OpenContainerSprite != 0)
+ {
+ var (tex, _, _) = SpriteResolve(OpenContainerSprite);
+ if (tex != 0)
+ ctx.DrawSprite(tex, 0f, 0f, Width, Height, 0f, 0f, 1f, 1f, Vector4.One);
+ }
+ if (Selected && SpriteResolve is not null && SelectedSprite != 0)
+ {
+ var (tex, _, _) = SpriteResolve(SelectedSprite);
+ if (tex != 0)
+ ctx.DrawSprite(tex, 0f, 0f, Width, Height, 0f, 0f, 1f, 1f, Vector4.One);
+ }
+```
+
+- [ ] **Step 5: Run the tests to verify they pass**
+
+Run: `dotnet test tests/AcDream.App.Tests/AcDream.App.Tests.csproj --filter "FullyQualifiedName~UiItemSlotTests"`
+Expected: PASS.
+
+- [ ] **Step 6: Commit**
+
+```bash
+git add src/AcDream.App/UI/UiItemSlot.cs tests/AcDream.App.Tests/UI/UiItemSlotTests.cs
+git commit -m "feat(D.2b): UiItemSlot open-container triangle + selected-item square overlays
+
+Co-Authored-By: Claude Opus 4.8 (1M context) "
+```
+
+---
+
+## Task 5: `InventoryController` container-switching + indicators
+
+**Files:**
+- Modify: `src/AcDream.App/UI/Layout/InventoryController.cs` (state, `Bind` signature, `Populate`, click handlers, `ApplyIndicators`, `Concerns`, caption)
+- Test: `tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs`
+
+- [ ] **Step 1: Extend the test `Bind` helper + write the failing tests**
+
+In `InventoryControllerTests.cs`, replace the private `Bind` helper (lines 53-57) with:
+
+```csharp
+ private static InventoryController Bind(ImportedLayout layout, ClientObjectTable objects,
+ int? strength = 100, List? uses = null, List? closes = null)
+ => InventoryController.Bind(layout, objects, () => Player,
+ iconIds: (_, _, _, _, _) => 0u, // no real GL upload in tests
+ strength: () => strength, datFont: null,
+ sendUse: uses is null ? null : g => uses.Add(g),
+ sendNoLongerViewing: closes is null ? null : g => closes.Add(g));
+
+ // Seed a side bag (a container) in the player's pack, plus optionally its own contents.
+ private static void SeedBag(ClientObjectTable t, uint bag, int slot, int itemsCapacity = 24)
+ {
+ t.AddOrUpdate(new ClientObject { ObjectId = bag, Type = ItemType.Container, ItemsCapacity = itemsCapacity });
+ t.MoveItem(bag, Player, slot);
+ }
+```
+
+Then add these tests at the end of the class (before the closing brace):
+
+```csharp
+ [Fact]
+ public void ClickSideBag_sendsUse_andSwapsGridToBagContents()
+ {
+ var (layout, grid, containers, _, _, _, _, _) = BuildLayout();
+ var objects = new ClientObjectTable();
+ SeedContained(objects, 0xA, Player, slot: 0); // a loose main-pack item
+ SeedBag(objects, 0xC, slot: 1); // side bag (player slot 1)
+ SeedContained(objects, 0xB1, 0xC, slot: 0); // a thing already known to be in the bag
+ var uses = new List();
+ Bind(layout, objects, uses: uses);
+
+ // The side-bag column's first cell holds the bag guid; click it.
+ containers.GetItem(0)!.Clicked!();
+
+ Assert.Contains(0xCu, uses); // Use(bag) sent
+ Assert.Equal(0xB1u, grid.GetItem(0)!.ItemId); // grid swapped to the bag's contents
+ Assert.Equal(24, grid.GetNumUIItems()); // padded to the bag's ItemsCapacity
+ }
+
+ [Fact]
+ public void ClickMainPackCell_afterBag_closesBag_returnsToMainPack()
+ {
+ var (layout, grid, containers, top, _, _, _, _) = BuildLayout();
+ var objects = new ClientObjectTable();
+ SeedContained(objects, 0xA, Player, slot: 0); // loose main-pack item
+ SeedBag(objects, 0xC, slot: 1);
+ SeedContained(objects, 0xB1, 0xC, slot: 0);
+ var uses = new List();
+ var closes = new List();
+ var ctrl = Bind(layout, objects, uses: uses, closes: closes);
+
+ containers.GetItem(0)!.Clicked!(); // open the bag
+ top.GetItem(0)!.Clicked!(); // click the main-pack cell
+
+ Assert.Contains(0xCu, closes); // NoLongerViewingContents(bag) sent
+ Assert.DoesNotContain(Player, uses); // no Use for the main pack
+ Assert.Equal(0xAu, grid.GetItem(0)!.ItemId); // grid back to the main pack
+ Assert.Equal(102, grid.GetNumUIItems());
+ }
+
+ [Fact]
+ public void SwitchBetweenTwoBags_closesPrevious_opensNext()
+ {
+ var (layout, _, containers, _, _, _, _, _) = BuildLayout();
+ var objects = new ClientObjectTable();
+ SeedBag(objects, 0xC1, slot: 0);
+ SeedBag(objects, 0xC2, slot: 1);
+ var uses = new List();
+ var closes = new List();
+ Bind(layout, objects, uses: uses, closes: closes);
+
+ containers.GetItem(0)!.Clicked!(); // open bag A (column index 0 → 0xC1)
+ containers.GetItem(1)!.Clicked!(); // open bag B (column index 1 → 0xC2)
+
+ Assert.Equal(new[] { 0xC1u, 0xC2u }, uses.ToArray()); // Use(A) then Use(B)
+ Assert.Equal(new[] { 0xC1u }, closes.ToArray()); // close A when switching to B (not the main pack)
+ }
+
+ [Fact]
+ public void OpenBag_marksTriangleAndSquare_onTheBagCell()
+ {
+ var (layout, _, containers, _, _, _, _, _) = BuildLayout();
+ var objects = new ClientObjectTable();
+ SeedBag(objects, 0xC, slot: 0);
+ Bind(layout, objects, uses: new List());
+
+ containers.GetItem(0)!.Clicked!();
+
+ Assert.True(containers.GetItem(0)!.IsOpenContainer); // triangle on the open bag
+ Assert.True(containers.GetItem(0)!.Selected); // square — the bag is also the selected item
+ }
+
+ [Fact]
+ public void ClickGridItem_movesSquareOnly_noWire_keepsOpenContainer()
+ {
+ var (layout, grid, _, top, _, _, _, _) = BuildLayout();
+ var objects = new ClientObjectTable();
+ SeedContained(objects, 0xA, Player, slot: 0);
+ var uses = new List();
+ var closes = new List();
+ Bind(layout, objects, uses: uses, closes: closes);
+
+ grid.GetItem(0)!.Clicked!(); // select the loose item
+
+ Assert.True(grid.GetItem(0)!.Selected); // square on the selected grid item
+ Assert.True(top.GetItem(0)!.IsOpenContainer); // main pack still the open container (unchanged)
+ Assert.Empty(uses); // selection sends no wire
+ Assert.Empty(closes);
+ }
+
+ [Fact]
+ public void Default_mainPackCell_isOpenContainer()
+ {
+ var (layout, _, _, top, _, _, _, _) = BuildLayout();
+ var objects = new ClientObjectTable();
+ Bind(layout, objects);
+ Assert.True(top.GetItem(0)!.IsOpenContainer); // default open container = main pack
+ }
+```
+
+Note: `BuildLayout()` returns `top` as the 4th tuple element (the `_topContainer` UiItemList); the existing tests discard it with `_`. The new tests above bind it where needed.
+
+- [ ] **Step 2: Run the tests to verify they fail**
+
+Run: `dotnet test tests/AcDream.App.Tests/AcDream.App.Tests.csproj --filter "FullyQualifiedName~InventoryControllerTests"`
+Expected: FAIL — `InventoryController.Bind` has no `sendUse`/`sendNoLongerViewing` parameters (compile error).
+
+- [ ] **Step 3: Add controller state + new ctor/Bind parameters**
+
+In `InventoryController.cs`:
+
+(a) Add constant near `MainPackSlots` (~line 39):
+```csharp
+ private const int SidePackSlots = 24; // standard side-pack capacity (reference_retail_inventory_paperdoll)
+```
+
+(b) Add fields near `_burdenPercent` (~line 52):
+```csharp
+ private uint _openContainer; // 0 = the main pack (the player); else the open side bag's guid
+ private uint _selectedItem; // 0 = none; the panel-wide selected item (green square)
+ private readonly Action? _sendUse;
+ private readonly Action? _sendNoLongerViewing;
+```
+
+(c) Add ctor parameters (append to the existing private ctor parameter list, after `mainPackEmptySprite`):
+```csharp
+ uint mainPackEmptySprite,
+ Action? sendUse,
+ Action? sendNoLongerViewing)
+```
+and assign them at the top of the ctor body (after `_strength = strength;`):
+```csharp
+ _sendUse = sendUse;
+ _sendNoLongerViewing = sendNoLongerViewing;
+```
+
+(d) Add the same two parameters to the public `Bind` (after `mainPackEmptySprite = 0u`), and pass them through:
+```csharp
+ uint mainPackEmptySprite = 0u,
+ Action? sendUse = null,
+ Action? sendNoLongerViewing = null)
+ => new InventoryController(layout, objects, playerGuid, iconIds, strength, datFont,
+ contentsEmptySprite, sideBagEmptySprite, mainPackEmptySprite,
+ sendUse, sendNoLongerViewing);
+```
+
+- [ ] **Step 4: Replace `Populate` + add the new private methods**
+
+Replace the entire `Populate` method body with:
+
+```csharp
+ public void Populate()
+ {
+ uint p = _playerGuid();
+ uint open = EffectiveOpen();
+
+ _contentsGrid?.Flush();
+ _containerList?.Flush();
+
+ // Side-bag column: ALWAYS the player's bags (constant across container switches; only the
+ // open/selected indicators move). Equipped items never appear here.
+ foreach (var guid in _objects.GetContents(p))
+ {
+ var item = _objects.Get(guid);
+ if (item is null || item.CurrentlyEquippedLocation != EquipMask.None) continue;
+ bool isBag = item.Type.HasFlag(ItemType.Container) || item.ItemsCapacity > 0;
+ if (isBag) AddCell(_containerList, guid, isContainer: true);
+ }
+
+ // Contents grid: the OPEN container's loose items. (Bags live in the column; a side bag has
+ // no sub-bags, so the isBag skip is a no-op when a bag is open.)
+ foreach (var guid in _objects.GetContents(open))
+ {
+ var item = _objects.Get(guid);
+ if (item is null || item.CurrentlyEquippedLocation != EquipMask.None) continue;
+ bool isBag = item.Type.HasFlag(ItemType.Container) || item.ItemsCapacity > 0;
+ if (!isBag) AddCell(_contentsGrid, guid, isContainer: false);
+ }
+
+ // Pad the grid to the OPEN container's capacity (main pack 102 / side bag 24).
+ if (_contentsGrid is not null)
+ {
+ int cap = _objects.Get(open)?.ItemsCapacity ?? 0;
+ int slots = cap > 0 ? cap : (open == p ? MainPackSlots : SidePackSlots);
+ while (_contentsGrid.GetNumUIItems() < slots) AddEmptyCell(_contentsGrid);
+ }
+
+ // Pad the side-bag column to capacity, clamped to the 7-slot column (AP-52).
+ if (_containerList is not null)
+ {
+ int capacity = _objects.Get(p)?.ContainersCapacity ?? 0;
+ int bags = _containerList.GetNumUIItems();
+ int slots = capacity > 0 ? capacity : SideBagSlots;
+ slots = Math.Max(slots, bags);
+ slots = Math.Min(slots, SideBagSlots);
+ while (_containerList.GetNumUIItems() < slots) AddEmptyCell(_containerList);
+ }
+
+ // Main-pack cell: the player's own container — clicking it opens/selects the main pack.
+ if (_topContainer is not null)
+ {
+ _topContainer.Flush();
+ var main = new UiItemSlot { SpriteResolve = _topContainer.SpriteResolve };
+ main.SetItem(p, 0u);
+ main.Clicked = () => OpenContainer(p);
+ _topContainer.AddItem(main);
+ }
+
+ ApplyIndicators();
+ RefreshBurden();
+ }
+
+ /// The effective open container — the explicit one, or the player (main pack) by default.
+ /// Resolved live (not cached at ctor) so a late-arriving player guid is handled.
+ private uint EffectiveOpen() => _openContainer != 0 ? _openContainer : _playerGuid();
+
+ /// Add a populated cell wired to its click role: container cell → open+select,
+ /// item cell → select-only.
+ private void AddCell(UiItemList? list, uint guid, bool isContainer)
+ {
+ if (list is null) return;
+ var item = _objects.Get(guid);
+ uint tex = item is null ? 0u
+ : _iconIds(item.Type, item.IconId, item.IconUnderlayId, item.IconOverlayId, item.Effects);
+ var cell = new UiItemSlot { SpriteResolve = list.SpriteResolve };
+ cell.SetItem(guid, tex);
+ if (isContainer) cell.Clicked = () => OpenContainer(guid);
+ else cell.Clicked = () => SelectItem(guid);
+ list.AddItem(cell);
+ }
+
+ private static void AddEmptyCell(UiItemList list)
+ => list.AddItem(new UiItemSlot { SpriteResolve = list.SpriteResolve });
+
+ /// Select an item (panel-wide green square) without changing the open container or
+ /// touching the wire. Retail: UIElement_ItemList::ItemList_SetSelectedItem (0x004e2fe0).
+ private void SelectItem(uint guid)
+ {
+ if (guid == 0) return;
+ _selectedItem = guid;
+ ApplyIndicators();
+ }
+
+ /// Open a container (side bag or main pack): it becomes both the selected item and the
+ /// open container. Sends Use to open a side bag server-side (ViewContents arrives async), and
+ /// NoLongerViewingContents when switching away from a previously-open side bag. Retail:
+ /// gmBackpackUI container-selection + CM_Physics::Event_Use.
+ private void OpenContainer(uint guid)
+ {
+ if (guid == 0) return;
+ _selectedItem = guid; // the container cell is also the selected item
+ uint open = EffectiveOpen();
+ if (guid == open) { ApplyIndicators(); return; } // already open — just move the square
+
+ uint p = _playerGuid();
+ if (open != p && open != 0)
+ _sendNoLongerViewing?.Invoke(open); // close the previously-open side bag
+ _openContainer = guid;
+ if (guid != p)
+ _sendUse?.Invoke(guid); // open the side bag (ViewContents will land)
+ Populate(); // repaint the grid for the new open container
+ }
+
+ /// Stamp the open-container triangle + selected-item square onto every cell per the
+ /// retail keying (item.itemID == openContainerId / selectedItemId).
+ private void ApplyIndicators()
+ {
+ SetIndicators(_contentsGrid);
+ SetIndicators(_containerList);
+ SetIndicators(_topContainer);
+ }
+
+ private void SetIndicators(UiItemList? list)
+ {
+ if (list is null) return;
+ uint open = EffectiveOpen();
+ for (int i = 0; i < list.GetNumUIItems(); i++)
+ {
+ var cell = list.GetItem(i);
+ if (cell is null) continue;
+ cell.Selected = cell.ItemId != 0 && cell.ItemId == _selectedItem;
+ cell.IsOpenContainer = cell.ItemId != 0 && cell.ItemId == open;
+ }
+ }
+```
+
+- [ ] **Step 5: Extend `Concerns` + the caption**
+
+(a) In `Concerns`, add the open-container clause. Replace the return with:
+```csharp
+ uint p = _playerGuid();
+ return o.ObjectId == p // the player object IS the burden source
+ || o.ContainerId == p || o.WielderId == p
+ || o.ContainerId == EffectiveOpen() // the OPEN container's contents drive the grid
+ || (o.ContainerId != 0 && _objects.Get(o.ContainerId)?.ContainerId == p); // 2-deep
+```
+
+(b) In the ctor, change the contents-caption attach (currently `() => "Contents of Backpack"`) to follow the open container:
+```csharp
+ AttachCaption(layout.FindElement(ContentsCaptionId), () => "Contents of " + OpenContainerName(), datFont);
+```
+and add the helper near `EffectiveOpen`:
+```csharp
+ /// The open container's display name for the contents caption.
+ private string OpenContainerName()
+ {
+ uint open = EffectiveOpen();
+ return open == _playerGuid() ? "Backpack" : (_objects.Get(open)?.Name ?? "Backpack");
+ }
+```
+
+- [ ] **Step 6: Run the tests to verify they pass**
+
+Run: `dotnet test tests/AcDream.App.Tests/AcDream.App.Tests.csproj --filter "FullyQualifiedName~InventoryControllerTests"`
+Expected: PASS (the 6 new tests + all existing InventoryController tests).
+
+- [ ] **Step 7: Commit**
+
+```bash
+git add src/AcDream.App/UI/Layout/InventoryController.cs tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs
+git commit -m "feat(D.2b): InventoryController container-switching + open/selected indicators
+
+Co-Authored-By: Claude Opus 4.8 (1M context) "
+```
+
+---
+
+## Task 6: wire the send callbacks in `GameWindow`
+
+**Files:**
+- Modify: `src/AcDream.App/Rendering/GameWindow.cs:2231-2241` (the `InventoryController.Bind` call)
+
+**Test note:** `GameWindow` is integration-wired, not unit-tested; verified by build + the visual gate (Task 8).
+
+- [ ] **Step 1: Add the two callbacks to the Bind call**
+
+In `GameWindow.cs`, in the `InventoryController.Bind(...)` call (~line 2231), append two arguments after `mainPackEmptySprite: mainPackEmpty`:
+
+```csharp
+ contentsEmptySprite: contentsEmpty,
+ sideBagEmptySprite: sideBagEmpty,
+ mainPackEmptySprite: mainPackEmpty,
+ sendUse: g => _liveSession?.SendUse(g),
+ sendNoLongerViewing: g => _liveSession?.SendNoLongerViewingContents(g));
+```
+
+- [ ] **Step 2: Verify it compiles**
+
+Run: `dotnet build src/AcDream.App/AcDream.App.csproj`
+Expected: Build succeeded.
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add src/AcDream.App/Rendering/GameWindow.cs
+git commit -m "feat(D.2b): wire InventoryController container-open callbacks to the live session
+
+Co-Authored-By: Claude Opus 4.8 (1M context) "
+```
+
+---
+
+## Task 7: divergence register + docs
+
+**Files:**
+- Modify: `docs/architecture/retail-divergence-register.md` (retire AP-56; reword AP-53; add new rows)
+
+- [ ] **Step 1: Retire AP-56**
+
+Delete the AP-56 row (line ~158) — both indicators are now drawn.
+
+- [ ] **Step 2: Reword AP-53**
+
+Change AP-53's text from "the grid always shows the main pack (container-switch to a side pack's 24 not wired)" / "selecting a side pack doesn't show its 24-slot contents yet" to note that container-switching is now wired and the row covers only the capacity *default* (102/24 when `ItemsCapacity`/`ContainersCapacity` is absent).
+
+- [ ] **Step 3: Add the new rows** (use the next free AP-numbers after the current max; e.g. AP-57/AP-58):
+
+- A row: the open-container triangle (`0x06005D9C`) + selected-item square (`0x06004D21`) are drawn as **procedural `UiItemSlot` overlays** keyed by controller state (`_openContainer`/`_selectedItem`), reproducing the retail keying (`item.itemID == openContainerId / selectedItemId` per `UpdateOpenContainerIndicator 0x004e3070` / `ItemList_SetSelectedItem 0x004e2fe0`) but not via the dat prototype's `m_elem_Icon_OpenContainer`/`m_elem_Icon_Selected` state elements + `SetOpenContainerState`/`SetSelectedState` calls. File: `src/AcDream.App/UI/UiItemSlot.cs`, `src/AcDream.App/UI/Layout/InventoryController.cs`. Risk: a cell that should show an indicator via a dat-state path retail uses but we don't would be missed; outcome currently matches retail (the 36×36 container prototype lacks the square child, so the procedural overlay is the only way to show the square on a selected bag).
+- A row: inventory item **selection is panel-local + visual-only** — not wired to the selected-object bar (`SelectedObjectController`) or to global 3D-world selection. File: `src/AcDream.App/UI/Layout/InventoryController.cs`. Risk: selecting an inventory item doesn't populate the selected-object strip as retail does; deferred to the selection follow-up.
+
+- [ ] **Step 4: Commit**
+
+```bash
+git add docs/architecture/retail-divergence-register.md
+git commit -m "docs(D.2b): divergence register — retire AP-56, reword AP-53, add overlay/selection rows
+
+Co-Authored-By: Claude Opus 4.8 (1M context) "
+```
+
+---
+
+## Task 8: full-suite gate + visual verification
+
+**Files:** none (verification only).
+
+- [ ] **Step 1: Full build + full test suite**
+
+Run: `dotnet build` then `dotnet test`
+Expected: Build succeeded; ALL tests pass (run the FULL suite, not a filtered subset — the B-Wire process lesson: a filtered batch hid a cross-file regression).
+
+- [ ] **Step 2: Launch the client (plain `dotnet run`, DO NOT pre-kill any running client)**
+
+If a rebuild is locked by a running client, ASK the user to close it — do not Stop-Process. Launch (PowerShell, background, per CLAUDE.md):
+
+```powershell
+$env:ACDREAM_DAT_DIR="$env:USERPROFILE\Documents\Asheron's Call"; $env:ACDREAM_LIVE="1"; $env:ACDREAM_TEST_HOST="127.0.0.1"; $env:ACDREAM_TEST_PORT="9000"; $env:ACDREAM_TEST_USER="testaccount"; $env:ACDREAM_TEST_PASS="testpassword"; $env:ACDREAM_RETAIL_UI="1"
+dotnet run --project src\AcDream.App\AcDream.App.csproj --no-build -c Debug 2>&1 | Tee-Object -FilePath "launch.log"
+```
+
+- [ ] **Step 3: Capture the Use → ViewContents round-trip** (settles lazy-load-on-open)
+
+While the client is in-world with F12 open, capture loopback with WireMCP (`capture_packets` on the `127.0.0.1:9000` conversation) and/or grep `launch.log` for the ViewContents handler, while the user clicks a side bag. Confirm a `Use 0x0036` goes out and a `ViewContents 0x0196` comes back, and note whether the bag's contents arrived only on open.
+
+- [ ] **Step 4: Visual gate (the oracle — user confirms)**
+
+The user, with F12 open: clicks a side bag → grid swaps to its contents; the open bag shows the triangle; the clicked cell shows the green/yellow square; clicks another bag → grid + indicators follow + the previous bag is closed; clicks the main-pack cell → grid returns to the main pack. Iterate on any sprite/positioning mismatch (the visual gate is the oracle for WHICH sprite, per the empty-slot-art lesson).
+
+- [ ] **Step 5: Update SSOT + roadmap after the gate passes**
+
+Append a "container-switching SHIPPED" entry to `claude-memory/project_d2b_retail_ui.md` (key facts + any DO-NOT-RETRY from the gate), update the roadmap/milestones if a milestone marker moved, and record the lazy-load finding. Commit.
+
+---
+
+## Self-review
+
+**Spec coverage:** ReplaceContents (T1) ↔ spec §Components.1; ViewContents full-replace (T2) ↔ §Components.2; SendUse (T3) ↔ §Components.3; UiItemSlot overlays (T4) ↔ §Components.4; InventoryController state/Populate/clicks/indicators/Concerns/caption (T5) ↔ §Components.5; GameWindow wiring (T6) ↔ §Components.6; divergence rows (T7) ↔ §Divergence register; full suite + visual gate + lazy-load capture (T8) ↔ §Acceptance + §Open verification. All spec sections covered.
+
+**Placeholder scan:** every code step shows complete code; no TBD/TODO; the only "as appropriate" is T7's next-free-AP-number, which is mechanical (read the current max in the register).
+
+**Type consistency:** `ReplaceContents(uint, IReadOnlyList)` consistent T1↔T2. `SendUse(uint)` T3↔T6. `IsOpenContainer`/`OpenContainerSprite`/`Selected`/`SelectedSprite` consistent T4↔T5. `Bind(..., Action? sendUse, Action? sendNoLongerViewing)` consistent T5↔T6 (test helper)↔T6 (GameWindow). `EffectiveOpen()`/`OpenContainer()`/`SelectItem()`/`ApplyIndicators()`/`SetIndicators()`/`AddCell()`/`AddEmptyCell()`/`OpenContainerName()` all defined in T5. `SidePackSlots` const defined T5 step 3a.