Merge campaign-409-tooltips: hover-feedback completion — item names, world-object tooltips, item cursor swap

Item-name tooltips on every UiItemSlot surface (UIElement_UIItem::UpdateTooltip
@0x004E1CB0, stack-count prefix, the 47-prototype shared popup locator);
world-object hover tooltips via retail's SmartBox found-object pipeline
(RecvNotice_SmartBoxObjectFound @0x004E5AD0 — immediate, ShowTooltips-gated,
no stack prefix — live-verified: 'Silver Tusker' + DefaultFound cursor from
one pipeline); #411 CLOSED — retail's set_found_object fires unconditionally
over UI items, the user's memory was right, our target-mode gate was wrong.
TS-85 narrowed to the enumerated remainder.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/ISSUES.md

@@ -26,13 +26,33 @@ What does NOT go here:
 
 ## #411 — Hover feedback over interactive UI elements: no cursor swap, and item cells have no rollover state
 
-**Status:** OPEN (filed 2026-08-16 during the #409 live-failure investigation, at the
+**Status:** CLOSED 2026-08-16 at the #409 hover-feedback completion round — the
-lead's scope addition; user report: "the cursor should light up when I hover over an
+user's answer to the open question below ("the POINTER changes, like it already
-item in inventory. it does not")
+does over world NPCs") is CONFIRMED by decomp, not merely a memory to trust:
+`UIElement_SmartBoxWrapper::FindObject @0x004E5430` calls
+`SmartBox::set_found_object(itemID)` UNCONDITIONALLY whenever the hovered UI
+element casts to `UIElement_UIItem` — not gated on target mode, as the port plan
+below (written before this finding) assumed it would need to be. Fixed with a
+ONE-LINE widening of `CursorFeedbackController.Update(UiRoot)`'s existing
+(too-narrow) item-hover special case; `ResolveGlobalKind` needed no changes,
+since it already read the "found" flag unconditionally across every mode. See
+docs/ISSUES.md #409's own "hover-feedback completion round" write-up (item 3)
+for the full derivation and `CursorFeedbackControllerTests.
+UpdateFromRoot_HoveringAnItemSlot_ShowsFoundCursor_In{OrdinaryPeaceMode,CombatMode}`
+for the pin. The rollover-STATE half of this investigation (item 3 below,
+`UiItemSlot` has no `HoverEnter`/`HoverLeave`) was NOT in scope for the pointer
+question and remains unaddressed if the user separately wants the highlight —
+file a fresh issue if so; this closure covers only the pointer-swap question the
+lead's scope addition asked about.
+
 **Severity:** LOW (cosmetic/affordance; no gameplay impact)
 **Depends on:** nothing — the hover dispatch it needs is already correct (see #409's
 live-failure round, which proved `UiRoot.UpdateHover` selects the right widget).
 
+**Original investigation (below), kept for its still-valid layer 1/2/3 breakdown —
+only the "never fires over an inventory item" conclusion for layer 2 was
+incomplete; see the closure note above for the corrected reading.**
+
 **Retail mechanism, derived from `docs/research/named-retail/acclient_2013_pseudo_c.txt`.**
 There are THREE separate hover-feedback layers, and the DAT decides which one applies:
 
@@ -188,7 +208,7 @@ horizontal `HJustify` mapping while in this code, since it shares the
 
 ## #409 — Client-wide UI tooltip system is unshipped (GF-16, deferred out of Campaign CC gate round 1)
 
-**Status:** CODE-COMPLETE 2026-08-16; review-fix round F1-F11 and the LIVE-FAILURE round both landed same day. The live-failure round's own fix is LIVE-VERIFIED (Options -> Character tab tooltip observed on a real connected client, screenshot evidence); the user's full connected gate is still owed.
+**Status:** CODE-COMPLETE 2026-08-16; review-fix round F1-F11, the LIVE-FAILURE round, and the hover-feedback completion round (item-cell tooltips + world-object hover tooltip) all landed same day. The live-failure round's own fix is LIVE-VERIFIED (Options -> Character tab tooltip observed on a real connected client, screenshot evidence); the hover-feedback completion round's three items are automated-gate-verified (unit + live-DAT) but the user's connected gate for THOSE items specifically is still owed — see that round's own "Live-verify all three" note.
 **Severity:** LOW-MEDIUM (cosmetic/discoverability — no gameplay impact, but retail shows a tooltip on hover for authored elements client-wide and acdream showed none before this fix)
 
 **2026-08-16 re-derivation + port.** Full re-derivation from
@@ -353,16 +373,113 @@ the "Slots" button.
 spin arrows — longer text, should WRAP rather than run off-screen; (7) the
 Heritage/Profession/Skills/Town/Summary tab buttons.
 
-*Expected NOT to show anything yet (deferred, register TS-85):* hovering an
-inventory ITEM icon. Retail shows the item name there
-(`UIElement_UIItem::UpdateTooltip @0x004E1CB0`); acdream shows nothing.
-
 Confirm also: the box sits offset down-right of the cursor (retail's +32px on
 both axes), never runs off the edge of the window even near a corner, and
 disappears on its own after ~10 s if you hold still without moving away. No
 click-to-dismiss is expected — only moving off the control, or a very long
 hold, closes it.
 
+**2026-08-16 hover-feedback completion round.** Closes the two items the
+live-failure round explicitly deferred (item-cell tooltips, and the #411
+pointer question), plus the world-object hover tooltip the user's gate notes
+called out separately.
+
+1. **Inventory/shortcut/paperdoll item-name tooltips — SHIPPED.**
+   `UIElement_UIItem::UpdateTooltip @0x004E1CB0` is called from
+   `UIItem_Update` (an item-DATA-CHANGE refresh, not a hover handler — the
+   trigger that actually SHOWS it is the generic `CheckTooltip` dwell timer,
+   same as any other tooltip-bearing element). Re-derived and closed the gap
+   the live-failure round left open ("acdream's `UiItemSlot` carries neither
+   the `P0x47` popup locator nor a name source"): live-DAT sweep of the
+   shared UIItem cell-template catalog (`ItemListCellTemplate.CatalogLayoutId`,
+   `0x21000037`) found ALL 47 UIItem-type (class `0x10000032`) prototypes —
+   inventory's cell, every toolbar slot, every paperdoll/armor slot skin —
+   resolve the IDENTICAL popup locator (`P0x47=0x10000395`/`P0x48=0x21000041`)
+   through catalog inheritance, with no literal text authored on any of them
+   (`TooltipLiveDatTests.UiItemCatalog_EveryPrototype_SharesTheSamePopupLocator`).
+   `UiItemSlot` now hardcodes that pair and exposes `GetTooltipText()` via a
+   new per-instance `TooltipTextResolve` delegate, wired at every physical-
+   item construction site — `InventoryController` (main-pack cell + grid
+   cells), `ExternalContainerController`, `PaperdollController` (closes the
+   `gmPaperDollUI::UpdateItemSlotTooltip @0x004A52EF` row too — same cell
+   class, same fix), `VendorUiController` (shop/buying/selling lists),
+   `SecureTradeUiController`, `ToolbarController`. Text is
+   `ClientObject.GetTooltipDisplayName()` (new Core method): `GetAppropriateName()`
+   prefixed with the stack count via `"{count} {name}"` when `StackSize > 1`,
+   matching `UpdateTooltip`'s exact `NAME_APPROPRIATE` + `"%d %s"` sprintf.
+   `UiCatalogSlot` (spell/component catalog cells — a DIFFERENT `UiItemSlot`
+   subclass) is unaffected; it already overrides `GetTooltipText()` with its
+   own `Label`.
+
+2. **World-object hover tooltip (NPCs, players, signs, chests, portals) —
+   SHIPPED.** NOT the UI-element dwell-timer path — retail's mechanism is
+   `UIElement_SmartBoxWrapper::RecvNotice_SmartBoxObjectFound @0x004E5AD0`,
+   fed every frame by `FindObject @0x004E5430`/`Global_Loop @0x004E5620`
+   using the current mouse position regardless of input focus. It fires
+   IMMEDIATELY (no dwell wait) on the found-object id CHANGING, gated by the
+   `PlayerModule::ShowTooltips` character option (`CharacterOptionId.ShowTooltips`
+   — already modeled in `CharacterOptionTable`, default true), with text
+   `ACCWeenieObject::GetObjectName(id, NAME_APPROPRIATE, 0)` — the SAME name
+   call as item tooltips, but WITHOUT the item-cell's separate stack-count
+   prefix (a real, decomp-confirmed asymmetry: a ground pile of arrows shows
+   "Arrows", not "20 Arrows"). Ported as `RetailTooltipPresenter.
+   UpdateWorldHoverTooltip`, driven by the SAME world-hover pick
+   `CursorFeedbackController`'s own found-cursor already uses
+   (`WorldSelectionQuery.PickAtCursor`, `includeSelf: true`) and the SAME
+   `ClientObjectTable`-backed name resolver `SocialAllegiancePageController`'s
+   `ResolveWorldObjectName` already established as this codebase's pattern.
+   Queried only when no UI element is hovered (this port's reading of
+   `FindObject`'s `m_pElementLastOver` check, narrowed from retail's literal
+   "raycast even under non-item UI chrome" — see the class's own doc note).
+   **Own player is included** (`includeSelf: true`, the same precedent the
+   cursor feedback wiring already set) — no decomp evidence was found either
+   confirming or excluding self from the found-object pipeline, so this
+   follows the established local precedent rather than guessing fresh; flag
+   if that reads wrong in the live gate. **The exact popup skin is an
+   inference, not a measured value** — an exhaustive live-DAT sweep found
+   `UIElement_SmartBoxWrapper` (class `0x10000030`) has NO authored
+   `ElementDesc` anywhere installed (unlike every other tooltip trigger, it
+   is evidently constructed directly by `gmGamePlayUI`'s own mode setup, not
+   from a walkable LayoutDesc — `TooltipLiveDatTests.
+   SmartBoxWrapper_HasNoAuthoredElementDesc_AnywhereInstalled`), so its real
+   `P0x47`/`P0x48` cannot be read off the DAT the way the item catalog's can.
+   This port reuses the SAME pair every other game-code `SetTooltip` caller
+   in this family resolves to — the best-evidenced choice, called out in
+   register row TS-85 rather than silently assumed exact.
+
+3. **#411 resolved: retail DOES swap the pointer over inventory items,
+   unconditionally — the earlier investigation's "never fires over an
+   inventory item" finding was INCOMPLETE, not wrong about what it checked.**
+   The original #411 scan (below) correctly found no PER-ELEMENT authored
+   cursor on item cells and correctly found `SmartBox::get_found_object_id()`
+   is written only by `UIElement_SmartBoxWrapper` — but it had not yet traced
+   `FindObject @0x004E5430` far enough: when the currently-hovered UI element
+   (`m_pElementLastOver`) casts to `UIElement_UIItem` (class `0x10000032`),
+   `FindObject` calls `SmartBox::set_found_object(itemID, 0xFFFFFFFF)`
+   directly and returns WITHOUT running the 3D raycast — UNCONDITIONALLY, not
+   gated on target mode. `ClientUISystem::UpdateCursorState @0x00564630`
+   computes its "found" flag ONCE at the top of the function
+   (`ebx = SmartBox::get_found_object_id() != 0`, `@0x00564642`) and every
+   later branch (default/melee-missile/magic/use/examine/use-target/busy)
+   reads that SAME flag — so hovering an occupied item cell shows the
+   cursor's "...Found" variant in EVERY mode, not only during an active
+   `UseTarget` selection. `CursorFeedbackController.Update(UiRoot)` already
+   had the item-hover special case wired (from an earlier round) but
+   incorrectly gated it to `TargetMode.UseTarget` only; that one-line gate is
+   now removed — `ResolveGlobalKind`'s existing found/not-found branching
+   needed no changes at all, since it already read the snapshot's
+   `HoverTargetGuid` unconditionally across every mode. Live-DAT-independent
+   (pure decomp + unit fixture), so no DAT sweep was needed for this part;
+   two new `CursorFeedbackControllerTests` pin the widened behavior in
+   ordinary peace mode and in combat mode.
+
+**Live-verify all three on the connected client** (session-config launch,
+graceful close per the usual rules): hover an inventory item — a name
+tooltip should appear (with a count prefix for a stack) AND the mouse
+pointer should swap to its "found" variant; hover an NPC/creature — a name
+tooltip should appear immediately (no perceptible delay) if "Show Tooltips"
+is on; hover a sign/chest/portal similarly.
+
 ---
 
 **Original GF-16 filing (superseded by the re-derivation above; kept for

src/AcDream.App/Composition/InteractionRetainedUiComposition.cs

@@ -842,6 +842,17 @@ internal sealed class RetailInteractionRetainedUiCompositionFactory
                     d.Actions.Selection,
                     text => d.Communication.AddText(text, RetailLogTextType.ClientLocal)),
                 Cursor: new RetailUiCursorBindings(cursorFeedback, cursorManager),
+                // #409 follow-on ("Item 2"): world-object hover tooltip.
+                // Reuses the SAME world-hover pick cursorFeedback's own
+                // worldTargetProvider already calls (UIElement_SmartBoxWrapper::
+                // FindObject's 3D-raycast fallback — RetailWorldPicker's exact
+                // port) and the SAME ClientObjectTable name resolver
+                // ResolveWorldObjectName already uses elsewhere in this file.
+                WorldTooltip: new WorldTooltipRuntimeBindings(
+                    HoverGuidAtCursor: () => late.Selection.PickAtCursor(includeSelf: true),
+                    ResolveName: guid => d.Inventory.Objects.Get(guid)?.GetAppropriateName(),
+                    Enabled: () => d.Character.Options.GetOptionBit(
+                        CharacterOptionId.ShowTooltips)),
                 Confirmations: new ConfirmationRuntimeBindings(
                     (type, context, accepted) =>
                         late.Session.CurrentSession?.SendConfirmationResponse(

src/AcDream.App/UI/CursorFeedbackController.cs

@@ -109,17 +109,32 @@ public sealed class CursorFeedbackController
 
         UiElement? hover = root.Pick(root.MouseX, root.MouseY);
 
-        // Retail UpdateCursorState (0x00564630) keys the target-mode cursor off
+        // Retail UpdateCursorState (0x00564630) keys EVERY mode's cursor off
-        // the SmartBox found object — the WORLD entity under the cursor. A UI
+        // the SAME SmartBox found-object flag, computed once at the top of
-        // window occludes the world (no found object → pending). The one
+        // the function (ebx = SmartBox::get_found_object_id() != 0,
-        // UI-side source retail-style cells contribute is an occupied item
+        // @0x00564642) and read verbatim by every later branch — target mode
-        // slot's own item.
+        // and combat mode only pick WHICH cursor variant (Default vs.
+        // DefaultFound, Use vs. UseFound, ...) to show for that SAME found
+        // state, never whether it is set.
+        //
+        // #411 correction (2026-08-16): the found object itself is not
+        // world-only. UIElement_SmartBoxWrapper::FindObject @0x004E5430 runs
+        // every frame regardless of input focus (Global_Loop @0x004E5620)
+        // and, when the currently-hovered UI element (m_pElementLastOver)
+        // casts to UIElement_UIItem (0x10000032), calls
+        // SmartBox::set_found_object(itemID) directly — UNCONDITIONALLY, not
+        // gated on target mode — and returns WITHOUT running the 3D raycast.
+        // So hovering an occupied item cell sets the SAME found flag in
+        // EVERY mode (peace, melee/missile, magic, busy, examine, use,
+        // use-target), which is why retail's cursor visibly changes there —
+        // the earlier reading here (item slots only contribute in
+        // UseTarget) covered only the Valid/Invalid sub-branch, not the
+        // found flag driving the Default/Combat/Use/Examine/Busy Found
+        // variants too.
         RetailCursorTargetMode targetMode = ModeFromInteraction(_itemInteraction);
         uint hoverTarget = hover is null
             ? _worldTargetProvider?.Invoke() ?? 0u
-            : targetMode == RetailCursorTargetMode.UseTarget
+            : FindHoveredItemSlot(hover)?.ItemId ?? 0u;
-                ? FindHoveredItemSlot(hover)?.ItemId ?? 0u
-                : 0u;
         bool? hoverTargetCompatible = targetMode == RetailCursorTargetMode.UseTarget
             && hoverTarget != 0
                 ? _itemInteraction?.IsCurrentTargetCompatible(hoverTarget)

src/AcDream.App/UI/Layout/ExternalContainerController.cs

@@ -363,6 +363,7 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
             SpriteResolve = owner.SpriteResolve,
             SlotIndex = owner.GetNumUIItems(),
             SourceKind = source,
+            TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
         };
         cell.SetItem(guid, icon, dragIconTexture: dragIcon);
         return cell;

src/AcDream.App/UI/Layout/InventoryController.cs

@@ -444,7 +444,11 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
         {
             const uint PlayerPackBaseIcon = 0x0600127Eu;   // constant main-pack backpack (visual gate)
             _topContainer.Flush();
-            var main = new UiItemSlot { SpriteResolve = _topContainer.SpriteResolve };
+            var main = new UiItemSlot
+            {
+                SpriteResolve = _topContainer.SpriteResolve,
+                TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
+            };
             main.SetItem(
                 p,
                 _iconIds(ItemType.Container, PlayerPackBaseIcon, 0u, 0u, 0u),
@@ -486,7 +490,11 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
         uint dragTex = item is null ? 0u
             : _dragIconIds?.Invoke(
                 item.Type, item.IconId, item.IconUnderlayId, item.IconOverlayId, item.Effects) ?? 0u;
-        var cell = new UiItemSlot { SpriteResolve = list.SpriteResolve };
+        var cell = new UiItemSlot
+        {
+            SpriteResolve = list.SpriteResolve,
+            TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
+        };
         cell.SetItem(guid, tex, dragIconTexture: dragTex);
         cell.SetWaitingState(waiting);
         cell.SlotIndex = list.GetNumUIItems();                 // index it will occupy (== its slot in a packed list)

src/AcDream.App/UI/Layout/PaperdollController.cs

@@ -88,6 +88,7 @@ public sealed class PaperdollController : IItemListDragHandler, IRetainedPanelCo
             list.ExamineItemRequested = ExamineItem;
             list.Cell.SourceKind  = ItemDragSource.Equipment;
             list.Cell.SlotIndex   = i;              // definition position = equipped drag-payload SourceSlot
+            list.Cell.TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName();
             list.Cell.EmptySprite = emptySlotSprites is not null
                 && emptySlotSprites.TryGetValue(element, out uint authoredSprite)
                     ? authoredSprite

src/AcDream.App/UI/Layout/RetailTooltipPresenter.cs

@@ -173,20 +173,36 @@ public sealed class RetailTooltipPresenter : IDisposable
         if (layoutDid == 0u)
             return;
 
+        if (TryBuildAndMountPopup(widget.AuthoredTooltipRootElementId, layoutDid, tooltipText!))
+            _owner = widget;
+    }
+
+    /// <summary>
+    /// Shared popup-build/mount body for BOTH tooltip triggers this class
+    /// owns: the UI-element hover-dwell path above (<see cref="OnTooltipShow"/>,
+    /// per-widget authored <c>P0x47</c>/<c>P0x48</c>) and the world-object
+    /// hover path below (<see cref="UpdateWorldHoverTooltip"/>, the fixed
+    /// popup-skin pair every game-code <c>SetTooltip</c> caller in this
+    /// family resolves to). Extracted unchanged from the pre-#411-follow-on
+    /// <c>OnTooltipShow</c> body — same F4/F5/F8 fixes, same failure
+    /// handling.
+    /// </summary>
+    private bool TryBuildAndMountPopup(uint rootElementId, uint layoutDid, string tooltipText)
+    {
         ImportedLayout? layout;
         try
         {
-            layout = _createLayout(layoutDid, widget.AuthoredTooltipRootElementId);
+            layout = _createLayout(layoutDid, rootElementId);
         }
         catch (Exception error)
         {
             Console.WriteLine(
                 $"[UI] #409 tooltip popup layout=0x{layoutDid:X8} "
-                + $"root=0x{widget.AuthoredTooltipRootElementId:X8} failed to build: {error.Message}");
+                + $"root=0x{rootElementId:X8} failed to build: {error.Message}");
-            return;
+            return false;
         }
         if (layout is null)
-            return;
+            return false;
 
         UiElement root = layout.Root;
         UiElement? textChild = root.AuthoredTooltipTextChildElementId != 0u
@@ -202,7 +218,7 @@ public sealed class RetailTooltipPresenter : IDisposable
         // show an empty, unsized 30x30 bevel artifact instead of retail's
         // silent no-op.
         if (textChild is not UiText text)
-            return;
+            return false;
 
         // F4: null the per-frame anchor recompute on BOTH the popup root and
         // its text child before resizing, the same shape the sibling
@@ -216,7 +232,7 @@ public sealed class RetailTooltipPresenter : IDisposable
         text.LayoutPolicy = null;
         text.Anchors = AnchorEdges.None;
 
-        ApplyTooltipText(root, text, tooltipText!);
+        ApplyTooltipText(root, text, tooltipText);
 
         SetClickThroughRecursive(root);
         PositionAtMouse(root);
@@ -224,7 +240,7 @@ public sealed class RetailTooltipPresenter : IDisposable
         _host.AddChild(root);
         _host.BringToFront(root);
         _popupRoot = root;
-        _owner = widget;
+        return true;
     }
 
     private void OnTooltipHide(UiElement widget)
@@ -240,6 +256,122 @@ public sealed class RetailTooltipPresenter : IDisposable
         _host.RemoveChild(_popupRoot);
         _popupRoot = null;
         _owner = null;
+        _worldTooltipShowing = false;
+    }
+
+    // ── World-object hover tooltip (docs/ISSUES.md #409 follow-on) ─────────
+    //
+    // Port of UIElement_SmartBoxWrapper::RecvNotice_SmartBoxObjectFound
+    // @0x004E5AD0's tooltip half (@0x004E5D13-@0x004E5E00). Unlike the
+    // dwell-timer UI-element path above, this trigger is EDGE-fired: retail
+    // calls SetTooltip + StartTooltipAtMouse IMMEDIATELY when SmartBox's
+    // found-object id CHANGES (@0x004E5D74/@0x004E5DFB) — no dwell wait —
+    // gated per-edge by PlayerModule::ShowTooltips (@0x004E5D21,
+    // CharacterOptionId.ShowTooltips in this port's CharacterOptionTable).
+    // The text is ACCWeenieObject::GetObjectName(id, NAME_APPROPRIATE, 0)
+    // (@0x004E5D3B) — the SAME call UIElement_UIItem::UpdateTooltip uses,
+    // but WITHOUT that item-cell's separate stack-count "%d %s" prefix
+    // (RecvNotice_SmartBoxObjectFound's own text-building block has no
+    // count logic at all — a real, decomp-confirmed asymmetry versus
+    // UiItemSlot's GetTooltipDisplayName).
+    //
+    // The found-object id itself comes from UIElement_SmartBoxWrapper::
+    // FindObject @0x004E5430, called every frame from Global_Loop
+    // @0x004E5620 using the CURRENT mouse position regardless of what has
+    // input focus. FindObject special-cases m_pElementLastOver casting to
+    // UIElement_UIItem (SmartBox::set_found_object(itemID) — item cells
+    // own their own answer, ported as UiItemSlot.GetTooltipText, Item 1);
+    // otherwise it runs the ordinary 3D raycast even under non-item UI
+    // chrome. This port narrows that second branch to "no UI element
+    // hovered at all" (see WorldHoverGuidProvider's own doc) rather than
+    // reproducing the raycast-under-windows edge case.
+    //
+    // UIElement_SmartBoxWrapper is registered class 0x10000030
+    // (Register @0x0047A47E) but an exhaustive live-DAT sweep
+    // (TooltipLiveDatTests.SmartBoxWrapper_HasNoAuthoredElementDesc_
+    // AnywhereInstalled) found ZERO elements of that type anywhere
+    // installed — unlike the UIItem catalog's 49 standalone template
+    // prototypes, the 3D-viewport wrapper is evidently constructed
+    // directly by gmGamePlayUI's own mode setup rather than from a
+    // walkable authored ElementDesc, so its own P0x47/P0x48 cannot be
+    // read from the DAT. This port therefore REUSES the item catalog's
+    // confirmed uniform popup-locator pair (WorldPopupRootElementId/
+    // WorldPopupLayoutDid below) — the SAME "generic runtime-text" skin
+    // every other game-code SetTooltip caller in this family draws from —
+    // as the best-evidenced inference for the unrecoverable constant.
+
+    /// <summary>Same popup skin every UIItem prototype resolves to
+    /// (<see cref="UiItemSlot"/>'s own <c>ItemTooltipRootElementId</c>) —
+    /// see this section's own doc note on why the exact value cannot be
+    /// read off an authored <c>UIElement_SmartBoxWrapper</c> ElementDesc.</summary>
+    private const uint WorldPopupRootElementId = 0x10000395u;
+    private const uint WorldPopupLayoutDid = 0x21000041u;
+
+    private uint _worldHoverGuid;
+    private bool _worldTooltipShowing;
+
+    /// <summary>
+    /// The world-hover pick (retail's <c>SmartBox::find_object</c> via
+    /// <c>UIElement_SmartBoxWrapper::FindObject @0x004E5430</c>'s fallback
+    /// branch) — a per-frame "what's under the cursor right now" query,
+    /// distinct from click-driven <c>SelectionState</c>. Queried only when
+    /// <see cref="UiRoot.Pick"/> finds no UI element under the cursor
+    /// (mirrors <c>FindObject</c>'s <c>m_pElementLastOver</c> check, narrowed
+    /// per this section's own doc note). Null/unset disables the whole
+    /// world-hover path (no world tooltip, matching a client build that
+    /// never wires it).
+    /// </summary>
+    public Func<uint?>? WorldHoverGuidProvider { get; set; }
+
+    /// <summary>
+    /// <c>ACCWeenieObject::GetObjectName(id, NAME_APPROPRIATE, 0)</c> —
+    /// resolve the found guid's display name. Returning null/empty shows no
+    /// tooltip for that guid (matching retail's own non-empty-string guard
+    /// at <c>@0x004E5D48</c>).
+    /// </summary>
+    public Func<uint, string?>? WorldHoverNameResolver { get; set; }
+
+    /// <summary>
+    /// <c>PlayerModule::ShowTooltips</c> (<c>CharacterOptionId.ShowTooltips</c>) —
+    /// read once per found-object edge, exactly where retail reads it
+    /// (<c>@0x004E5D21</c>). A mid-hover option toggle takes effect at the
+    /// NEXT found-object change, matching retail's own edge-only
+    /// re-evaluation rather than a live per-frame re-check.
+    /// </summary>
+    public Func<bool>? WorldTooltipsEnabled { get; set; }
+
+    private void UpdateWorldHoverTooltip()
+    {
+        if (WorldHoverGuidProvider is null)
+            return;
+
+        uint found = _host.Pick(_host.MouseX, _host.MouseY) is null
+            ? WorldHoverGuidProvider() ?? 0u
+            : 0u;
+
+        if (found == _worldHoverGuid)
+            return;   // no change -> RecvNotice_SmartBoxObjectFound never re-fires
+        _worldHoverGuid = found;
+
+        if (found == 0u)
+        {
+            if (_worldTooltipShowing)
+                RemovePopup();
+            return;
+        }
+
+        if (WorldTooltipsEnabled?.Invoke() != true)
+            return;
+
+        string? text = WorldHoverNameResolver?.Invoke(found);
+        if (string.IsNullOrEmpty(text))
+            return;
+
+        // A UI-element popup cannot be showing here: UiRoot's own hover
+        // (queried above) is null whenever this branch runs, so its dwell
+        // timer never arms and OnTooltipShow never fires concurrently.
+        if (TryBuildAndMountPopup(WorldPopupRootElementId, WorldPopupLayoutDid, text))
+            _worldTooltipShowing = true;
     }
 
     /// <summary>Force-hides whatever tooltip is currently showing, if any.
@@ -371,6 +503,8 @@ public sealed class RetailTooltipPresenter : IDisposable
     {
         if (_popupRoot is not null)
             _host.BringToFront(_popupRoot);
+
+        UpdateWorldHoverTooltip();
     }
 
     public void Dispose()

src/AcDream.App/UI/Layout/SecureTradeUiController.cs

@@ -295,6 +295,7 @@ public sealed class SecureTradeUiController : IRetainedPanelController
                     // Your staged items carry retail's trading marker.
                     ShowTradeOverlay = side == RuntimeTradeSide.Self,
                     TradeOverlaySprite = TradeOverlaySpriteId,
+                    TooltipTextResolve = g => _bindings.Objects.Get(g)?.GetTooltipDisplayName(),
                 };
                 cell.SetItem(guid, icon);
                 list.AddItem(cell);

src/AcDream.App/UI/Layout/ToolbarController.cs

@@ -145,6 +145,7 @@ public sealed class ToolbarController : IItemListDragHandler, IRetainedPanelCont
                 list.Cell.SlotIndex  = i;
                 list.Cell.SourceKind = ItemDragSource.ShortcutBar;
                 list.Cell.DragAcceptSprite = 0x060011FAu;   // green cross (toolbar), not the ring 0x060011F9 (inventory)
+                list.Cell.TooltipTextResolve = g => _repo.Get(g)?.GetTooltipDisplayName();
             }
         }
 

src/AcDream.App/UI/Layout/VendorUiController.cs

@@ -1102,6 +1102,10 @@ public sealed class VendorUiController : IRetainedPanelController, IItemListDrag
                         // comment for why this must be gated at the source,
                         // not left to every destination handler to reject.
                         AllowDragSource = false,
+                        // Shop items are materialized into ClientObjectTable
+                        // (VendorShopItemMaterializer), so the same resolver
+                        // every other physical cell uses works here too.
+                        TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
                     };
                     cell.SetItem(item.ItemGuid, icon);
                     cell.Selected = item.ItemGuid == selectedGuid;
@@ -2205,6 +2209,7 @@ public sealed class VendorUiController : IRetainedPanelController, IItemListDrag
                     SpriteResolve = list.SpriteResolve,
                     SlotIndex = list.GetNumUIItems(),
                     AllowDragSource = false,
+                    TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
                 };
                 cell.SetItem(shopItem.ItemGuid, icon);
                 cell.Selected = shopItem.ItemGuid == selectedGuid;
@@ -2243,6 +2248,7 @@ public sealed class VendorUiController : IRetainedPanelController, IItemListDrag
                     SpriteResolve = list.SpriteResolve,
                     SlotIndex = list.GetNumUIItems(),
                     AllowDragSource = false,
+                    TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
                 };
                 cell.SetItem(item.ObjectId, icon);
                 cell.Selected = item.ObjectId == selectedGuid;

src/AcDream.App/UI/RetailUiRuntime.cs

@@ -333,6 +333,17 @@ public sealed record RetailUiCursorBindings(
     CursorFeedbackController Feedback,
     RetailCursorManager Manager);
 
+/// <summary>
+/// #409 follow-on (docs/ISSUES.md "Item 2"): world-object hover tooltip
+/// bindings for <see cref="RetailTooltipPresenter"/>'s world-hover half — see
+/// that class's own doc note on <c>UIElement_SmartBoxWrapper::
+/// RecvNotice_SmartBoxObjectFound @0x004E5AD0</c>.
+/// </summary>
+public sealed record WorldTooltipRuntimeBindings(
+    Func<uint?> HoverGuidAtCursor,
+    Func<uint, string?> ResolveName,
+    Func<bool> Enabled);
+
 public sealed record ConfirmationRuntimeBindings(
     Action<uint, uint, bool> SendResponse);
 
@@ -435,6 +446,7 @@ public sealed record RetailUiRuntimeBindings(
     ExternalContainerRuntimeBindings ExternalContainer,
     VendorRuntimeBindings Vendor,
     RetailUiCursorBindings Cursor,
+    WorldTooltipRuntimeBindings WorldTooltip,
     ConfirmationRuntimeBindings Confirmations,
     AppraisalRuntimeBindings Appraisal,
     OptionsRuntimeBindings Options,
@@ -3366,7 +3378,15 @@ public sealed class RetailUiRuntime : IDisposable
             }
         }
 
-        TooltipPresenter = new RetailTooltipPresenter(Host.Root, CreateTooltipLayout);
+        TooltipPresenter = new RetailTooltipPresenter(Host.Root, CreateTooltipLayout)
+        {
+            // #409 follow-on ("Item 2"): the world-object hover half —
+            // see RetailTooltipPresenter's own doc note on
+            // UIElement_SmartBoxWrapper::RecvNotice_SmartBoxObjectFound.
+            WorldHoverGuidProvider = () => _bindings.WorldTooltip.HoverGuidAtCursor(),
+            WorldHoverNameResolver = _bindings.WorldTooltip.ResolveName,
+            WorldTooltipsEnabled = () => _bindings.WorldTooltip.Enabled(),
+        };
 
         if (_bindings.Chat.Store is { } store)
         {

src/AcDream.App/UI/UiItemSlot.cs

@@ -12,13 +12,63 @@ namespace AcDream.App.UI;
 /// </summary>
 public class UiItemSlot : UiElement
 {
-    public UiItemSlot() { ClickThrough = false; }
+    /// <summary>
+    /// Retail's shared UIItem cell-template catalog (<c>ItemListCellTemplate.
+    /// CatalogLayoutId</c>, LayoutDesc <c>0x21000037</c>) authors the SAME
+    /// tooltip popup locator on every one of its 49 standalone prototypes —
+    /// live-DAT-probed 2026-08-16: every top-level catalog child (inventory's
+    /// 32x32 cell <c>0x1000033A</c>, the toolbar's per-slot prototypes
+    /// <c>0x1000043B</c>.., the container cell <c>0x1000033F</c>, and every
+    /// paperdoll/armor slot skin alike) resolves <c>P0x47=0x10000395</c> /
+    /// <c>P0x48=0x21000041</c> through catalog inheritance, matching one of
+    /// the four popup skins <see cref="Layout.RetailTooltipPresenter"/> already
+    /// mounts for every other tooltip-bearing element
+    /// (<c>Layout.TooltipLiveDatTests.PopupSkinRootIds</c>). Since
+    /// <see cref="UiItemSlot"/> cells are built programmatically (never through
+    /// <c>LayoutImporter.Build</c>), this port hardcodes the uniform pair here
+    /// rather than re-deriving it per instance — the same "exhaustive scan,
+    /// then hardcode" shape as <c>RetailCursorCatalog</c>'s five window-control
+    /// cursor DIDs and <c>ItemListCellTemplate.CatalogLayoutId</c> itself.
+    /// </summary>
+    private const uint ItemTooltipRootElementId = 0x10000395u;
+    private const uint ItemTooltipLayoutDid = 0x21000041u;
+
+    public UiItemSlot()
+    {
+        ClickThrough = false;
+        AuthoredTooltipRootElementId = ItemTooltipRootElementId;
+        AuthoredTooltipLayoutDid = ItemTooltipLayoutDid;
+    }
 
     public override bool ConsumesDatChildren => true;
 
     /// <summary>Bound weenie guid (0 = empty). Retail UIElement_UIItem::itemID.</summary>
     public uint ItemId { get; private set; }
 
+    /// <summary>
+    /// Resolves <see cref="ItemId"/> to its retail tooltip text (a
+    /// <see cref="AcDream.Core.Items.ClientObject.GetTooltipDisplayName"/>
+    /// call bound by the owning controller — every construction site already
+    /// has a <c>ClientObjectTable</c> reference in scope, matching how
+    /// <see cref="SpriteResolve"/> is wired). Null/empty result shows no
+    /// tooltip, matching retail's <c>UIItem_Update</c> early-out
+    /// (<c>weenObj == 0</c> -&gt; <c>UIElement::ClearTooltip</c>) for an
+    /// empty or not-yet-materialized cell.
+    /// </summary>
+    public Func<uint, string?>? TooltipTextResolve { get; set; }
+
+    /// <summary>
+    /// Port of <c>UIElement_UIItem::UpdateTooltip @0x004E1CB0</c>: called every
+    /// refresh (retail's own callers are heartbeat/state-change driven), but
+    /// computed lazily here — the same "runtime text on demand" shape already
+    /// established by <see cref="UiButton.GetTooltipText"/> and
+    /// <see cref="UiRadar.GetTooltipText"/> — rather than cached at
+    /// <see cref="SetItem"/> time, since nothing observes a stale value between
+    /// item-state changes and the next hover dwell.
+    /// </summary>
+    public override string? GetTooltipText()
+        => ItemId != 0 ? TooltipTextResolve?.Invoke(ItemId) : null;
+
     /// <summary>Pre-composited icon GL texture for the bound item (0 = none).</summary>
     public uint IconTexture { get; private set; }
 

src/AcDream.Core/Items/ClientObject.cs

@@ -347,6 +347,22 @@ public sealed class ClientObject
         if (string.IsNullOrEmpty(Name)) return Name;
         return Name[^1] == 's' ? Name + "es" : Name + "s";
     }
+
+    /// <summary>
+    /// Ports <c>UIElement_UIItem::UpdateTooltip @0x004E1CB0</c> — the item-cell
+    /// hover-tooltip text every physical item/container/shortcut cell shows.
+    /// Retail resolves the name with <c>NAME_APPROPRIATE</c> (the same call
+    /// <see cref="GetAppropriateName"/> already ports) and, only when the stack
+    /// holds more than one (<c>_stackSize_1 &gt; 1 @0x004e1d12</c>), prefixes the
+    /// count via <c>PStringBase&lt;unsigned short&gt;::sprintf(&amp;__return,
+    /// u"%d %s")</c> — count first, one space, then the (already
+    /// singular-or-plural) name.
+    /// </summary>
+    public string GetTooltipDisplayName()
+    {
+        string name = GetAppropriateName();
+        return StackSize > 1 ? $"{StackSize} {name}" : name;
+    }
 }
 
 /// <summary>

tests/AcDream.App.Tests/UI/CursorFeedbackControllerTests.cs

@@ -308,6 +308,51 @@ public sealed class CursorFeedbackControllerTests
         Assert.False(feedback.Cursor.IsValid);
     }
 
+    /// <summary>
+    /// #411 fix (2026-08-16): UIElement_SmartBoxWrapper::FindObject
+    /// @0x004E5430 calls SmartBox::set_found_object(itemID) whenever the
+    /// hovered UI element casts to UIElement_UIItem, UNCONDITIONALLY — not
+    /// only in TARGET_MODE_USE_TARGET. ClientUISystem::UpdateCursorState
+    /// @0x00564630 then reads that SAME found flag from every mode branch
+    /// (Default/Combat/Use/Examine/Busy), so hovering an occupied item cell
+    /// in ordinary peace mode (no active interaction mode at all) must show
+    /// the Found cursor variant. This is the earlier-STOPped "does retail
+    /// swap the pointer over inventory items" question, resolved: yes,
+    /// unconditionally.
+    /// </summary>
+    [Fact]
+    public void UpdateFromRoot_HoveringAnItemSlot_ShowsFoundCursor_InOrdinaryPeaceMode()
+    {
+        var root = new UiRoot { Width = 800, Height = 600 };
+        var slot = new UiItemSlot { Left = 10, Top = 10, Width = 32, Height = 32 };
+        slot.SetItem(Target, iconTexture: 1u);
+        root.AddChild(slot);
+        root.OnMouseMove(20, 20);
+        var c = new CursorFeedbackController();   // no ItemInteractionController — TargetMode.None throughout
+
+        var feedback = c.Update(root);
+
+        Assert.Equal(RetailGlobalCursorKind.DefaultFound, feedback.GlobalKind);
+    }
+
+    /// <summary>Same #411 fix, combat mode: the found flag is mode-
+    /// independent, so an item hover under an active combat stance shows
+    /// MeleeOrMissileFound, not the plain (not-found) MeleeOrMissile.</summary>
+    [Fact]
+    public void UpdateFromRoot_HoveringAnItemSlot_ShowsFoundCursor_InCombatMode()
+    {
+        var root = new UiRoot { Width = 800, Height = 600 };
+        var slot = new UiItemSlot { Left = 10, Top = 10, Width = 32, Height = 32 };
+        slot.SetItem(Target, iconTexture: 1u);
+        root.AddChild(slot);
+        root.OnMouseMove(20, 20);
+        var c = new CursorFeedbackController(combatModeProvider: () => CombatMode.Melee);
+
+        var feedback = c.Update(root);
+
+        Assert.Equal(RetailGlobalCursorKind.MeleeOrMissileFound, feedback.GlobalKind);
+    }
+
     [Fact]
     public void UpdateFromRoot_worldProviderDrivesTargetCursor_whenUiNotHovered()
     {

tests/AcDream.App.Tests/UI/Layout/RetailTooltipPresenterTests.cs

@@ -589,4 +589,148 @@ public sealed class RetailTooltipPresenterTests
             if (FindById(child, datElementId) is { } found) return found;
         return null;
     }
+
+    // ── World-object hover tooltip (docs/ISSUES.md #409 follow-on) ─────────
+    // Port of UIElement_SmartBoxWrapper::RecvNotice_SmartBoxObjectFound
+    // @0x004E5AD0: edge-fired (no dwell wait), gated by PlayerModule::
+    // ShowTooltips, uses the fixed popup-skin pair every game-code
+    // SetTooltip caller in this family shares (see RetailTooltipPresenter's
+    // own doc note on why UIElement_SmartBoxWrapper's own P0x47/P0x48
+    // cannot be read from the installed DAT).
+
+    private const uint WorldFoundGuid = 0x80000123u;
+
+    [Fact]
+    public void WorldHover_ShowsImmediately_NoDwellWait()
+    {
+        var (root, presenter, requests) = CreateHarness();
+        presenter.WorldHoverGuidProvider = () => WorldFoundGuid;
+        presenter.WorldHoverNameResolver = guid => guid == WorldFoundGuid ? "A Drudge" : null;
+        presenter.WorldTooltipsEnabled = () => true;
+        int childrenBefore = root.Children.Count;
+
+        // A single Tick — no root.Tick dwell timer involved at all, unlike
+        // every UI-element case above.
+        presenter.Tick();
+
+        Assert.Equal(childrenBefore + 1, root.Children.Count);
+        Assert.Single(requests, r => r == (0x21000041u, 0x10000395u));
+    }
+
+    [Fact]
+    public void WorldHover_HidesWhenTheFoundGuidClears()
+    {
+        var (root, presenter, _) = CreateHarness();
+        uint? found = WorldFoundGuid;
+        presenter.WorldHoverGuidProvider = () => found;
+        presenter.WorldHoverNameResolver = _ => "A Drudge";
+        presenter.WorldTooltipsEnabled = () => true;
+        int childrenBefore = root.Children.Count;
+
+        presenter.Tick();
+        Assert.Equal(childrenBefore + 1, root.Children.Count);
+
+        found = null;
+        presenter.Tick();
+
+        Assert.Equal(childrenBefore, root.Children.Count);
+    }
+
+    [Fact]
+    public void WorldHover_ShowTooltipsOff_ShowsNothing()
+    {
+        // PlayerModule::ShowTooltips @0x004E5D21 gates the whole block —
+        // UpdateCursorState (the found-cursor swap) is NOT gated by it, but
+        // that is a separate mechanism this presenter does not own.
+        var (root, presenter, requests) = CreateHarness();
+        presenter.WorldHoverGuidProvider = () => WorldFoundGuid;
+        presenter.WorldHoverNameResolver = _ => "A Drudge";
+        presenter.WorldTooltipsEnabled = () => false;
+        int childrenBefore = root.Children.Count;
+
+        presenter.Tick();
+
+        Assert.Empty(requests);
+        Assert.Equal(childrenBefore, root.Children.Count);
+    }
+
+    [Fact]
+    public void WorldHover_NoNameResolved_ShowsNothing()
+    {
+        var (_, presenter, requests) = CreateHarness();
+        presenter.WorldHoverGuidProvider = () => WorldFoundGuid;
+        presenter.WorldHoverNameResolver = _ => null;
+        presenter.WorldTooltipsEnabled = () => true;
+
+        presenter.Tick();
+
+        Assert.Empty(requests);
+    }
+
+    [Fact]
+    public void WorldHover_SuppressedWhileHoveringAUiElement()
+    {
+        // FindObject @0x004E5430: m_pElementLastOver != null routes through
+        // the UI-item special case or falls through to the 3D raycast —
+        // either way the found-object pipeline here must not also fire for
+        // whatever the mouse is currently over. This port narrows that to
+        // "no UI element hovered at all" (see the class's own doc note).
+        var (root, presenter, requests) = CreateHarness();
+        var uiElement = new HoverTarget { Left = 100, Top = 100, Width = 40, Height = 20 };
+        root.AddChild(uiElement);
+        root.OnMouseMove(110, 110);
+
+        presenter.WorldHoverGuidProvider = () => WorldFoundGuid;
+        presenter.WorldHoverNameResolver = _ => "A Drudge";
+        presenter.WorldTooltipsEnabled = () => true;
+
+        presenter.Tick();
+
+        Assert.Empty(requests);
+    }
+
+    [Fact]
+    public void WorldHover_ReEvaluatesGateAndTextOnlyOnTheFoundGuidEdge()
+    {
+        // RecvNotice_SmartBoxObjectFound only re-runs when SmartBox::
+        // set_found_object's target actually changes — a per-frame poll of
+        // the SAME found id must not re-read ShowTooltips or re-resolve the
+        // name every tick.
+        var (_, presenter, requests) = CreateHarness();
+        int gateReads = 0, nameReads = 0;
+        presenter.WorldHoverGuidProvider = () => WorldFoundGuid;
+        presenter.WorldHoverNameResolver = _ => { nameReads++; return "A Drudge"; };
+        presenter.WorldTooltipsEnabled = () => { gateReads++; return true; };
+
+        presenter.Tick();
+        presenter.Tick();
+        presenter.Tick();
+
+        Assert.Equal(1, gateReads);
+        Assert.Equal(1, nameReads);
+        Assert.Single(requests);
+    }
+
+    [Fact]
+    public void WorldHover_TextIsPlainAppropriateName_NoStackCountPrefix()
+    {
+        // RecvNotice_SmartBoxObjectFound's own text-building block
+        // (@0x004E5D3B-@0x004E5D74) has no "%d %s" stack-count logic —
+        // unlike UIElement_UIItem::UpdateTooltip's item-cell tooltip. The
+        // resolver contract here is plain GetAppropriateName, not
+        // GetTooltipDisplayName; this pin just documents the caller's
+        // resolver is free to return whatever plain text it wants and the
+        // presenter applies it verbatim (no separate count formatting is
+        // ever added by this class).
+        var (root, presenter, _) = CreateHarness();
+        presenter.WorldHoverGuidProvider = () => WorldFoundGuid;
+        presenter.WorldHoverNameResolver = _ => "Iron Bars";
+        presenter.WorldTooltipsEnabled = () => true;
+
+        presenter.Tick();
+
+        UiElement popup = Assert.Single(root.Children);
+        UiElement? textChild = FindById(popup, TextChildId);
+        Assert.IsType<UiText>(textChild);
+    }
 }

tests/AcDream.App.Tests/UI/Layout/TooltipLiveDatTests.cs

@@ -217,6 +217,125 @@ public sealed class TooltipLiveDatTests
     private const uint OptionsToggleRowTemplateId = 0x10000218u;
     private const uint OptionsToggleCheckboxId = 0x10000219u;
 
+    /// <summary>Retail's <c>UIElement_UIItem</c> registered class id
+    /// (<c>UIElement_UIItem::Register @0x0047A488</c>:
+    /// <c>RegisterElementClass(0x10000032, ...)</c>). The catalog also holds a
+    /// handful of type-3 (plain UIRegion) housekeeping elements used only as
+    /// BaseElement bases for the real prototypes below — never selected by any
+    /// list's own cell-template attribute, so they are excluded from this
+    /// scan.</summary>
+    private const uint UiItemElementType = 0x10000032u;
+
+    /// <summary>
+    /// Item-tooltip investigation (docs/ISSUES.md #409 follow-on): pins the
+    /// finding that justifies <c>UiItemSlot</c> hardcoding a single popup-
+    /// locator pair rather than reading it per prototype. Every standalone
+    /// UIItem prototype (type <c>0x10000032</c>) in the shared cell-template
+    /// catalog (<see cref="ItemListCellTemplate.CatalogLayoutId"/>, LayoutDesc
+    /// <c>0x21000037</c>) resolves the SAME <c>P0x47/P0x48</c> pair through
+    /// catalog inheritance — <c>0x10000395</c> within <c>0x21000041</c>, one of
+    /// the four popup skins <see cref="TooltipCatalog_EveryPopupSkin_SharesTheSameTextChild"/>
+    /// already pins. None author literal <c>P0x49</c> text or the <c>P0x4B</c>
+    /// on-bit — matching retail's runtime-text game-code sites
+    /// (<c>UIElement_UIItem::UpdateTooltip @0x004E1CB0</c> sets both the text
+    /// and the on-bit itself; see <see cref="RetailTooltipPresenter.OnTooltipShow"/>'s
+    /// <c>fromRuntime</c> bypass).
+    /// </summary>
+    [InstalledDatFact]
+    public void UiItemCatalog_EveryPrototype_SharesTheSamePopupLocator()
+    {
+        using var dats = new DatCollection(DatDirectory, DatAccessType.Read);
+
+        ElementInfo? catalog = LayoutImporter.ImportInfos(dats, ItemListCellTemplate.CatalogLayoutId);
+        Assert.NotNull(catalog);
+        Assert.True(catalog!.Children.Count >= 40,
+            $"expected the shared UIItem catalog to hold dozens of prototypes, found {catalog.Children.Count}.");
+
+        var prototypes = catalog.Children.Where(c => c.Type == UiItemElementType).ToList();
+        Assert.True(prototypes.Count >= 30,
+            $"expected the shared UIItem catalog to hold dozens of type-0x10000032 prototypes, found {prototypes.Count}.");
+
+        foreach (ElementInfo prototype in prototypes)
+        {
+            Assert.True(prototype.TooltipRootElementId == UiItemTooltipRootElementId,
+                $"prototype 0x{prototype.Id:X8} authors P0x47=0x{prototype.TooltipRootElementId:X8}, expected 0x{UiItemTooltipRootElementId:X8}.");
+            Assert.True(prototype.TooltipLayoutDid == TooltipCatalogLayoutId,
+                $"prototype 0x{prototype.Id:X8} authors P0x48=0x{prototype.TooltipLayoutDid:X8}, expected 0x{TooltipCatalogLayoutId:X8}.");
+            Assert.False(prototype.TooltipText.HasValue,
+                $"prototype 0x{prototype.Id:X8} unexpectedly authors literal P0x49 tooltip text.");
+        }
+
+        // Concrete owning lists select DIFFERENT prototype ids (attribute
+        // 0x1000000E) for their own cell shape, but every one of those
+        // prototypes still resolves the same popup locator above — so
+        // UiItemSlot's hardcoded pair is correct regardless of which list
+        // spawned the cell.
+        ElementInfo? inventoryTree = LayoutImporter.ImportInfos(dats, 0x21000023u);
+        ElementInfo? contentsGrid = inventoryTree is null
+            ? null : AllDescendants(inventoryTree).FirstOrDefault(x => x.Id == 0x100001C6u);
+        Assert.NotNull(contentsGrid);
+        Assert.True(contentsGrid!.TryGetEffectiveProperty(0x1000000Eu, out UiPropertyValue protoProp));
+        Assert.NotEqual(0u, (uint)protoProp.UnsignedValue);
+
+        ElementInfo? toolbarTree = LayoutImporter.ImportInfos(dats, 0x21000016u);
+        ElementInfo? toolbarSlot = toolbarTree is null
+            ? null : AllDescendants(toolbarTree).FirstOrDefault(x => x.Id == 0x100001A7u);
+        Assert.NotNull(toolbarSlot);
+        Assert.True(toolbarSlot!.TryGetEffectiveProperty(0x1000000Eu, out UiPropertyValue toolbarProtoProp));
+        Assert.NotEqual(0u, (uint)toolbarProtoProp.UnsignedValue);
+        // Different lists really do select different prototypes.
+        Assert.NotEqual((uint)protoProp.UnsignedValue, (uint)toolbarProtoProp.UnsignedValue);
+    }
+
+    /// <summary>
+    /// World-object tooltip investigation (docs/ISSUES.md #409 follow-on).
+    /// <c>UIElement_SmartBoxWrapper</c> (retail's registered class
+    /// <c>0x10000030</c>, <c>UIElement_SmartBoxWrapper::Register @0x0047A47E</c>)
+    /// is the caller of the world-hover tooltip's own
+    /// <c>UIElement::SetTooltip</c>/<c>StartTooltipAtMouse</c> pair
+    /// (<c>RecvNotice_SmartBoxObjectFound @0x004E5AD0</c>, calls at
+    /// <c>@0x004E5D74</c>/<c>@0x004E5DFB</c>) — but this exhaustive sweep of
+    /// every installed <c>LayoutDesc</c> found ZERO elements of that type
+    /// anywhere. Unlike the UIItem catalog (49 standalone template
+    /// prototypes, all authoring the SAME popup locator), the 3D-viewport
+    /// wrapper is evidently constructed directly by game code
+    /// (<c>gmGamePlayUI</c>'s own mode setup) rather than from a walkable
+    /// authored <c>ElementDesc</c>, so its own <c>P0x47</c>/<c>P0x48</c>
+    /// cannot be read from the DAT the way every other tooltip trigger's
+    /// can. <see cref="RetailTooltipPresenter"/>'s world-hover popup therefore
+    /// REUSES the item-catalog's confirmed uniform pair
+    /// (<c>P0x47=0x10000395</c>/<c>P0x48=0x21000041</c>) — the SAME "generic
+    /// runtime-text" skin every other game-code <c>SetTooltip</c> caller in
+    /// this family (items, the Options checkboxes, the radar) draws from —
+    /// as the best-evidenced inference rather than leaving world-object
+    /// tooltips unimplemented over one unrecoverable hex constant.
+    /// </summary>
+    [InstalledDatFact]
+    public void SmartBoxWrapper_HasNoAuthoredElementDesc_AnywhereInstalled()
+    {
+        using var dats = new DatCollection(DatDirectory, DatAccessType.Read);
+
+        int found = 0;
+        foreach (uint layoutId in dats.GetAllIdsOfType<LayoutDesc>())
+        {
+            ElementInfo? tree;
+            try { tree = LayoutImporter.ImportInfos(dats, layoutId); }
+            catch { continue; }
+            if (tree is null) continue;
+
+            found += AllDescendants(tree).Count(e => e.Type == SmartBoxWrapperElementType);
+        }
+
+        Assert.Equal(0, found);
+    }
+
+    /// <summary>Retail's <c>UIElement_SmartBoxWrapper</c> registered class id.</summary>
+    private const uint SmartBoxWrapperElementType = 0x10000030u;
+
+    /// <summary>The item-cell popup-locator P0x47, hardcoded onto every
+    /// <see cref="UiItemSlot"/> — see that class's own doc comment.</summary>
+    private const uint UiItemTooltipRootElementId = 0x10000395u;
+
     private static IEnumerable<UiElement> AllWidgets(UiElement root)
     {
         yield return root;