fix(ui): select retained items on mouse down

Port UIElement_ListBox's press-time selection ordering through the shared retained item-list contract. Inventory, loot, paperdoll, and physical shortcuts now update canonical selection before release or drag promotion, while target-mode consumption suppresses drag and release-time activation.

Co-authored-by: Codex <codex@openai.com>

AGENTS.md

@@ -115,8 +115,8 @@ and the final two-client portal-out/materialization observer flow are
 user-gated. Deterministic world-lifecycle automation protects fresh login,
 outdoor/world-edge/dungeon travel, same-location revisit, exact graceful
 disconnect, and uncapped fresh-process reconnect with JSON/PNG artifacts.
-Release builds; the appraisal corrective implementation passes 3,496 App
+Release builds; the appraisal and retained-item input corrections pass 3,548
-tests / 3 skips and 7,913 complete-solution tests / 5 skips.
+App tests / 3 skips and 7,979 complete-solution tests / 5 skips.
 
 **Current work order:** the six-slice pre-M4 world-interaction completion
 program in `docs/plans/2026-07-23-world-interaction-completion.md`: favorite
@@ -125,8 +125,8 @@ equipped-child picking, vendor browsing, and authoritative vendor
 transactions. Slices 1 and 2 plus the adjacent shared-cooldown presentation are
 user-accepted. Slice 3's first connected gate exposed and corrected the
 monster-response flag mismatch, non-retail shared-panel mounting, and missing
-inscription transaction. Its independent floaty examination window awaits the
+inscription transaction. The creature and common-item report corrections are
-corrective connected gate.
+user-accepted; press-time retained-item selection is the current visual gate.
 
 **Structural prerequisite before new M4 subsystem work:** all eight
 behavior-preserving `GameWindow` decomposition slices and the automated

CLAUDE.md

@@ -113,8 +113,8 @@ and the final two-client portal-out/materialization observer flow are
 user-gated. Deterministic world-lifecycle automation protects fresh login,
 outdoor/world-edge/dungeon travel, same-location revisit, exact graceful
 disconnect, and uncapped fresh-process reconnect with JSON/PNG artifacts.
-Release builds; the appraisal corrective implementation passes 3,496 App
+Release builds; the appraisal and retained-item input corrections pass 3,548
-tests / 3 skips and 7,913 complete-solution tests / 5 skips.
+App tests / 3 skips and 7,979 complete-solution tests / 5 skips.
 
 **Current work order:** the six-slice pre-M4 world-interaction completion
 program in `docs/plans/2026-07-23-world-interaction-completion.md`: favorite
@@ -123,8 +123,8 @@ equipped-child picking, vendor browsing, and authoritative vendor
 transactions. Slices 1 and 2 plus the adjacent shared-cooldown presentation are
 user-accepted. Slice 3's first connected gate exposed and corrected the
 monster-response flag mismatch, non-retail shared-panel mounting, and missing
-inscription transaction. Its independent floaty examination window awaits the
+inscription transaction. The creature and common-item report corrections are
-corrective connected gate.
+user-accepted; press-time retained-item selection is the current visual gate.
 
 **Structural prerequisite before new M4 subsystem work:** all eight
 behavior-preserving `GameWindow` decomposition slices and the automated

docs/ISSUES.md

@@ -151,6 +151,13 @@ The separate retained ItemList path now does the same for occupied backpack,
 side-bag, loot-container, paperdoll-slot, and physical shortcut cells; it
 selects the item before entering the shared appraisal owner, and RMB movement
 neither appraises nor lifts the item.
+The adjacent input-latency correction ports
+`UIElement_ListBox::MouseDown @ 0x0046E3A0`: physical retained items now update
+canonical selection and their green frame on left-button down, before the
+three-pixel drag threshold. Target mode is intercepted at that same press.
+Bag opening, item use/equip, and shortcut activation remain completed
+click/double-click actions, so a drag or target-consumed press cannot also
+activate the item.
 
 **Files:** `src/AcDream.Core.Net/Messages/AppraiseInfoParser.cs`;
 `src/AcDream.App/UI/RetailUiRuntime.cs`;
@@ -176,6 +183,8 @@ Right-clicking a visible world object opens the same examination window;
 right-dragging the camera does not.
 Right-clicking an occupied retained item cell selects and examines it without
 using, equipping, looting, or dragging it.
+Left-pressing one selects it before the button is released; holding and
+dragging preserves that selection without activating the item.
 The Black Phyntos Hive specifically reads `Value: ???`, `Burden: Unknown`,
 then its description after one retail paragraph break, without the bogus
 255-item/255-container line.

docs/plans/2026-04-11-roadmap.md

@@ -35,7 +35,10 @@ the configurable `SelectRight` action's retail release-completed gesture,
 including drag cancellation, then reuses the canonical
 picker/selection/appraisal path. The parallel retained ItemList branch now
 selects and appraises occupied inventory, external-container, paperdoll, and
-physical-shortcut cells through the same request owner. Slice 3's first connected gate exposed
+physical-shortcut cells through the same request owner. Its shared physical
+left-click contract now also matches retail's press-time selection: the
+selection frame updates on MouseDown before drag promotion, while completed
+click/double-click remains the activation boundary. Slice 3's first connected gate exposed
 three deeper defects, now corrected: the response enum mislabeled ACE's
 creature bit `0x0100` and dropped monster packets while retaining the busy
 cursor; the imported 310 x 400 examination layout was incorrectly hosted as

docs/plans/2026-05-12-milestones.md

@@ -104,6 +104,10 @@ instead of appraising the release point.
 Retail's separate retained ItemList right-click branch now covers physical
 backpack, loot, paperdoll, and toolbar item cells through the same selection
 and appraisal owner.
+The same shared ItemList contract now ports retail's left-button-down
+selection timing across inventory, loot, paperdoll, and physical shortcuts:
+selection is visible before release or drag promotion, while use/open/equip
+remains release-completed.
 Slice 3's first connected gate found and corrected the real remaining defects:
 ACE creature flag `0x0100` was mislabeled as a weapon profile and left the
 appraisal busy reference held, retail's examination UI had been mounted as a

docs/plans/2026-07-23-world-interaction-completion.md

@@ -222,9 +222,10 @@ present in the authored base name. Empty `AddItemInfo` calls are retained as
 real report fragments, restoring retail's intentional blank rows after
 workmanship, before armor level, around rating/special-property blocks, and at
 the later use/item-level boundaries. Focused wire, projection, object-table,
-title, and boots-layout fixtures protect the full path. The Release solution
+title, and boots-layout fixtures protect the full path. With the subsequent
-build and 3,533 App tests / 3 skips plus 7,956 complete-solution tests /
+right-click and press-time retained-item input ports, the Release solution
-5 skips pass; the connected boots comparison is the remaining visual gate.
+build and 3,548 App tests / 3 skips plus 7,979 complete-solution tests /
+5 skips pass.
 
 The world right-click follow-up ports
 `UIElement_SmartBoxWrapper::MouseUp @ 0x004E5820` and the
@@ -241,6 +242,13 @@ The retained follow-up ports the separate
 backpack, side-bag, loot, paperdoll-slot, or physical toolbar cell now selects
 its item and enters that same appraisal owner on a completed right-click.
 Right-button movement cancels the click and can never begin an item drag.
+The input-latency follow-up ports `UIElement_ListBox::MouseDown @ 0x0046E3A0`
+and the physical left-click branch of
+`UIElement_ItemList::ListenToElementMessage @ 0x004E4D50`. Canonical selection
+and the retained green frame update during left-button down, before the
+three-pixel drag threshold. Target mode is offered first. Opening, using,
+equipping, looting, and shortcut activation remain completed-click or
+double-click actions and are suppressed when target mode consumed the press.
 
 ## Slice 1 — spell-bar overflow arrows
 

docs/research/2026-07-17-retail-world-selection-pseudocode.md

@@ -190,6 +190,52 @@ procedural arrow. The indicator is persistent selection presentation. Retail
 also has a separate, short-lived click confirmation owned by SmartBox; it is not
 implemented in `CPhysicsPart::Draw` or `ACCWeenieObject::SetSelected`.
 
+## Retained physical-item press, activation, and drag ordering
+
+`UIElement_ListBox::MouseDown @ 0x0046E3A0`
+
+```text
+on left mouse down over a single-selection ListBox:
+    item = GetItemUnderMouse()
+    if item exists:
+        SetSelectedItem(item, notify=true)
+        if drag-selection is enabled:
+            StartDragSelect()
+```
+
+`UIElement_ItemList::ListenToElementMessage @ 0x004E4D50`
+
+```text
+on the physical-item left-button-down notice:
+    item = UIItem under the mouse
+    if a target mode is active:
+        HandleTargetedUseLeftClick(item)
+        consume the notice
+    else if item.itemID != 0:
+        if this list uses single selection:
+            update the list selection
+        SetSelectedObject(item.itemID)
+
+on the physical-item double-click notice:
+    if item.itemID != 0:
+        UseObject(item.itemID)
+```
+
+`gmPaperDollUI::ListenToElementMessage @ 0x004A5C30` uses the same ordering
+for a worn item: target mode first, otherwise set the selected object on the
+left-button-down notice; right-click selects and examines.
+
+Therefore selection is not a completed-click action. The green selection frame
+appears while the left button is still held, before the three-pixel drag
+threshold can promote the press into a drag. Opening a bag, using/equipping an
+item, and shortcut activation remain completed click or double-click actions,
+so dragging never also activates the source. A target-mode-consumed press
+suppresses the rest of that physical-item click gesture.
+
+Acdream implements that split once in `UiItemList`/`UiItemSlot`. Inventory,
+external-container loot, paperdoll equipment, and physical toolbar shortcuts
+only supply their selection source and release-time activation command.
+
 ## Right-click selection and examination
 
 `UIElement_SmartBoxWrapper::MouseUp @ 0x004E5820`

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

@@ -83,6 +83,9 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
         ConfigureList(_topContainer, ContainerCellSize, horizontalScroll: false, containerEmptySprite);
         ConfigureList(_containerList, ContainerCellSize, horizontalScroll: true, containerEmptySprite);
         ConfigureList(_contentsList, ItemCellSize, horizontalScroll: true, contentsEmptySprite);
+        _topContainer.PrimaryItemPressed = PressItem;
+        _containerList.PrimaryItemPressed = PressItem;
+        _contentsList.PrimaryItemPressed = PressItem;
         _topContainer.ExamineItemRequested = ExamineItem;
         _containerList.ExamineItemRequested = ExamineItem;
         _contentsList.ExamineItemRequested = ExamineItem;
@@ -325,7 +328,6 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
     private void AddRootCell(uint guid)
     {
         UiItemSlot cell = CreateCell(_topContainer, guid, ItemDragSource.Ground);
-        cell.Clicked = () => HandlePrimaryClick(guid, () => Select(guid));
         cell.DoubleClicked = RequestClose;
         cell.IsOpenContainer = _openContainer == guid;
         SetCapacity(cell, guid);
@@ -335,7 +337,7 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
     private void AddContainerCell(uint guid)
     {
         UiItemSlot cell = CreateCell(_containerList, guid, ItemDragSource.Ground);
-        cell.Clicked = () => HandlePrimaryClick(guid, () => OpenNestedContainer(guid));
+        cell.Clicked = () => OpenNestedContainer(guid);
         SetCapacity(cell, guid);
         _containerList.AddItem(cell);
     }
@@ -343,7 +345,6 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
     private void AddContentsCell(uint guid)
     {
         UiItemSlot cell = CreateCell(_contentsList, guid, ItemDragSource.Ground);
-        cell.Clicked = () => HandlePrimaryClick(guid, () => Select(guid));
         cell.DoubleClicked = () => _itemInteraction.ActivateItem(guid);
         cell.DragAcceptSprite = 0x060011F9u;
         cell.DragRejectSprite = 0x060011F8u;
@@ -384,11 +385,12 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
         _itemInteraction.ExamineSelectedOrEnterMode(guid);
     }
 
-    private void HandlePrimaryClick(uint guid, Action fallback)
+    private bool PressItem(uint guid)
     {
         if (_itemInteraction.OfferPrimaryClick(guid) != ItemPrimaryClickResult.NotActive)
-            return;
+            return true;
-        fallback();
+        Select(guid);
+        return false;
     }
 
     private void ApplyIndicators()
@@ -573,6 +575,9 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
         _objects.Cleared -= OnObjectsCleared;
         _selection.Changed -= OnSelectionChanged;
         _itemInteraction.StateChanged -= OnInteractionStateChanged;
+        _topContainer.PrimaryItemPressed = null;
+        _containerList.PrimaryItemPressed = null;
+        _contentsList.PrimaryItemPressed = null;
         _topContainer.ExamineItemRequested = null;
         _containerList.ExamineItemRequested = null;
         _contentsList.ExamineItemRequested = null;

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

@@ -153,9 +153,21 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
         _contentsGrid?.RegisterDragHandler(this);
         _containerList?.RegisterDragHandler(this);
         _topContainer?.RegisterDragHandler(this);
-        if (_contentsGrid is not null) _contentsGrid.ExamineItemRequested = ExamineItem;
+        if (_contentsGrid is not null)
-        if (_containerList is not null) _containerList.ExamineItemRequested = ExamineItem;
+        {
-        if (_topContainer is not null) _topContainer.ExamineItemRequested = ExamineItem;
+            _contentsGrid.PrimaryItemPressed = PressItem;
+            _contentsGrid.ExamineItemRequested = ExamineItem;
+        }
+        if (_containerList is not null)
+        {
+            _containerList.PrimaryItemPressed = PressItem;
+            _containerList.ExamineItemRequested = ExamineItem;
+        }
+        if (_topContainer is not null)
+        {
+            _topContainer.PrimaryItemPressed = PressSelfItem;
+            _topContainer.ExamineItemRequested = ExamineItem;
+        }
 
         // Burden meter: vertical 11×58 bar (gmBackpackUI m_burdenMeter, retail direction 4).
         _burdenMeter = layout.FindElement(BurdenMeterId) as UiMeter;
@@ -432,12 +444,7 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
                 dragIconTexture: _dragIconIds?.Invoke(
                     ItemType.Container, PlayerPackBaseIcon, 0u, 0u, 0u) ?? 0u);
             main.DragAcceptSprite = 0x060011F7u; main.DragRejectSprite = 0x060011F8u;
-            main.Clicked = () =>
+            main.Clicked = () => OpenContainer(p);
-            {
-                if (_itemInteraction?.OfferSelfPrimaryClick()
-                    is not null and not ItemPrimaryClickResult.NotActive) return;
-                OpenContainer(p);
-            };
             main.DoubleClicked = () => _itemInteraction?.ActivateItem(p);
             SetCapacityBar(main, p);               // main-pack fullness (items / ItemsCapacity)
             _topContainer.AddItem(main);
@@ -480,22 +487,28 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
         cell.DoubleClicked = () => _itemInteraction?.ActivateItem(guid);
         if (isContainer)
         {
-            cell.Clicked = () => HandlePrimaryClick(guid, () => OpenContainer(guid));
+            cell.Clicked = () => OpenContainer(guid);
             SetCapacityBar(cell, guid);
         }
-        else
-        {
-            cell.Clicked = () => HandlePrimaryClick(guid, () => SelectItem(guid));
-        }
         list.AddItem(cell);
     }
 
-    private void HandlePrimaryClick(uint guid, Action fallback)
+    private bool PressItem(uint guid)
     {
         if (_itemInteraction?.OfferPrimaryClick(guid)
             is not null and not ItemPrimaryClickResult.NotActive)
-            return;
+            return true;
-        fallback();
+        SelectItem(guid);
+        return false;
+    }
+
+    private bool PressSelfItem(uint guid)
+    {
+        if (_itemInteraction?.OfferSelfPrimaryClick()
+            is not null and not ItemPrimaryClickResult.NotActive)
+            return true;
+        SelectItem(guid);
+        return false;
     }
 
     private void AddEmptyCell(UiItemList list)
@@ -931,9 +944,21 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
         _objects.ObjectUpdated -= OnObjectChanged;
         _objects.Cleared       -= OnObjectsCleared;
         _selection.Changed -= OnSelectionChanged;
-        if (_contentsGrid is not null) _contentsGrid.ExamineItemRequested = null;
+        if (_contentsGrid is not null)
-        if (_containerList is not null) _containerList.ExamineItemRequested = null;
+        {
-        if (_topContainer is not null) _topContainer.ExamineItemRequested = null;
+            _contentsGrid.PrimaryItemPressed = null;
+            _contentsGrid.ExamineItemRequested = null;
+        }
+        if (_containerList is not null)
+        {
+            _containerList.PrimaryItemPressed = null;
+            _containerList.ExamineItemRequested = null;
+        }
+        if (_topContainer is not null)
+        {
+            _topContainer.PrimaryItemPressed = null;
+            _topContainer.ExamineItemRequested = null;
+        }
         if (_itemInteraction is not null)
         {
             _itemInteraction.StateChanged -= OnInteractionStateChanged;

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

@@ -84,6 +84,7 @@ public sealed class PaperdollController : IItemListDragHandler, IRetainedPanelCo
             var (element, mask, _, unlockBit) = PaperdollSlotBackgrounds.Definitions[i];
             if (layout.FindElement(element) is not UiItemList list) continue;
             list.RegisterDragHandler(this);
+            list.PrimaryItemPressed = PressItem;
             list.ExamineItemRequested = ExamineItem;
             list.Cell.SourceKind  = ItemDragSource.Equipment;
             list.Cell.SlotIndex   = i;              // definition position = equipped drag-payload SourceSlot
@@ -91,15 +92,6 @@ public sealed class PaperdollController : IItemListDragHandler, IRetainedPanelCo
                 && emptySlotSprites.TryGetValue(element, out uint authoredSprite)
                     ? authoredSprite
                     : emptySlotSprite;
-            list.Cell.Clicked = () =>
-            {
-                uint itemId = list.Cell.ItemId;
-                if (itemId != 0 && _itemInteraction?.OfferPrimaryClick(itemId)
-                    is not null and not ItemPrimaryClickResult.NotActive)
-                    return;
-                if (itemId != 0)
-                    _selection.Select(itemId, SelectionChangeSource.Paperdoll);
-            };
             list.Cell.DoubleClicked = () =>
             {
                 if (list.Cell.ItemId != 0)
@@ -357,6 +349,14 @@ public sealed class PaperdollController : IItemListDragHandler, IRetainedPanelCo
         _itemInteraction.ExamineSelectedOrEnterMode(itemId);
     }
 
+    private bool PressItem(uint itemId)
+    {
+        if (_itemInteraction.OfferPrimaryClick(itemId) != ItemPrimaryClickResult.NotActive)
+            return true;
+        _selection.Select(itemId, SelectionChangeSource.Paperdoll);
+        return false;
+    }
+
     /// <summary>Detach event handlers (idempotent).</summary>
     public void Dispose()
     {
@@ -369,7 +369,10 @@ public sealed class PaperdollController : IItemListDragHandler, IRetainedPanelCo
         _objects.Cleared       -= OnObjectsCleared;
         _selection.Changed -= OnSelectionChanged;
         foreach (var (_, list) in _slots)
+        {
+            list.PrimaryItemPressed = null;
             list.ExamineItemRequested = null;
+        }
         if (_dollViewport is UiViewport doll)
             doll.ClickedAt = null;
         switch (_dollDragMask)

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

@@ -138,6 +138,7 @@ public sealed class ToolbarController : IItemListDragHandler, IRetainedPanelCont
             if (_slots[i] is { } list)
             {
                 WireClick(list);
+                list.PrimaryItemPressed = PressItem;
                 list.ExamineItemRequested = ExamineItem;
                 // B.1 drag-drop spine: this controller is the drop handler for every
                 // toolbar slot list; each cell knows its slot index + that it's a
@@ -532,6 +533,19 @@ public sealed class ToolbarController : IItemListDragHandler, IRetainedPanelCont
         };
     }
 
+    private bool PressItem(uint itemId)
+    {
+        if (_itemInteraction?.OfferPrimaryClick(itemId)
+            is not null and not ItemPrimaryClickResult.NotActive)
+            return true;
+
+        if (_selectItem is not null)
+            _selectItem(itemId);
+        else
+            _selection?.Select(itemId, SelectionChangeSource.Toolbar);
+        return false;
+    }
+
     private void ExamineItem(uint itemId)
     {
         if (_selectItem is not null)
@@ -777,7 +791,10 @@ public sealed class ToolbarController : IItemListDragHandler, IRetainedPanelCont
             _selection.Changed -= OnSelectionChanged;
         foreach (UiItemList? list in _slots)
             if (list is not null)
+            {
+                list.PrimaryItemPressed = null;
                 list.ExamineItemRequested = null;
+            }
         _repo.ObjectAdded   -= OnRepositoryObjectChanged;
         _repo.ObjectUpdated -= OnRepositoryObjectChanged;
         _repo.ObjectRemoved -= OnRepositoryObjectChanged;

src/AcDream.App/UI/UiItemList.cs

@@ -73,6 +73,20 @@ public sealed class UiItemList : UiElement
     /// </summary>
     public Action<object, int, int>? CatalogDropped { get; set; }
 
+    /// <summary>
+    /// Physical-item left-button-down command supplied by the owning panel.
+    /// Return <see langword="true"/> when a target mode consumed the press so
+    /// the slot suppresses drag promotion and the completed Click/DoubleClick
+    /// gesture.
+    ///
+    /// Retail references:
+    /// <c>UIElement_ListBox::MouseDown @ 0x0046E3A0</c> selects the item under
+    /// the pointer during MouseDown, before optional drag selection;
+    /// <c>UIElement_ItemList::ListenToElementMessage @ 0x004E4D50</c> handles
+    /// target mode before ordinary physical-item selection.
+    /// </summary>
+    public Func<uint, bool>? PrimaryItemPressed { get; set; }
+
     /// <summary>
     /// Appraisal command supplied by the owning panel controller for physical
     /// item cells. Retail <c>UIElement_ItemList::ListenToElementMessage

src/AcDream.App/UI/UiItemSlot.cs

@@ -99,6 +99,7 @@ public class UiItemSlot : UiElement
 
     private bool _waiting;
     internal bool WaitingVisual => _waiting;
+    private bool _primaryPressConsumed;
 
     /// <summary>RenderSurface id -> (GL texture, w, h). Set by the factory/controller.</summary>
     public Func<uint, (uint tex, int w, int h)>? SpriteResolve { get; set; }
@@ -134,11 +135,14 @@ public class UiItemSlot : UiElement
         DragIconTexture = 0;
         Shortcut = null;
         _waiting = false;
+        _primaryPressConsumed = false;
     }
 
     /// <inheritdoc/>
     public override object? GetDragPayload()
-        => ItemId != 0 ? new ItemDragPayload(ItemId, SourceKind, SlotIndex, this, Shortcut) : null;
+        => ItemId != 0 && !_primaryPressConsumed
+            ? new ItemDragPayload(ItemId, SourceKind, SlotIndex, this, Shortcut)
+            : null;
 
     /// <inheritdoc/>
     public override (uint tex, int w, int h)? GetDragGhost()
@@ -251,8 +255,10 @@ public class UiItemSlot : UiElement
 
     // ── Events / draw ─────────────────────────────────────────────────────────
 
-    /// <summary>Invoked by <see cref="OnEvent"/> when a left-button-down lands on
+    /// <summary>Invoked by <see cref="OnEvent"/> when a completed left click lands
-    /// a bound slot. Wired by <c>ToolbarController</c> to the use-item callback.</summary>
+    /// on a bound slot. Selection already occurred on MouseDown through the owning
+    /// <see cref="UiItemList"/>; this callback performs release-time activation
+    /// such as opening a bag or using a shortcut.</summary>
     public Action? Clicked { get; set; }
 
     /// <summary>Invoked by <see cref="OnEvent"/> when a double-click lands on a bound slot.</summary>
@@ -267,12 +273,21 @@ public class UiItemSlot : UiElement
             // drag (press + >3px move) does NOT also use the item. UiRoot suppresses the
             // post-drag Click (UiRoot.cs FinishDrag returns before the Click emit).
             case UiEventType.MouseDown:
-                return true;                       // consume the press; no use here
+                // UIElement_ListBox::MouseDown @ 0x0046E3A0 selects immediately,
+                // before StartDragSelect. UIElement_ItemList's notice handler
+                // intercepts target mode first. Activation remains release-time,
+                // so a press promoted to drag never also uses the item.
+                _primaryPressConsumed = ItemId != 0
+                    && FindList() is { PrimaryItemPressed: { } pressed }
+                    && pressed(ItemId);
+                return true;
             case UiEventType.Click:
-                Clicked?.Invoke();
+                if (!_primaryPressConsumed)
+                    Clicked?.Invoke();
                 return true;
             case UiEventType.DoubleClick:
-                DoubleClicked?.Invoke();
+                if (!_primaryPressConsumed)
+                    DoubleClicked?.Invoke();
                 return true;
             case UiEventType.RightClick:
                 if (ItemId != 0

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

@@ -275,6 +275,61 @@ public class DragDropSpineTests
         Assert.True(used);
     }
 
+    [Fact]
+    public void PhysicalItemPress_selectsBeforeRelease_thenClickActivates()
+    {
+        var (root, list, cell) = RootWithBoundSlot(0x5001u);
+        var selected = new List<uint>();
+        bool used = false;
+        list.PrimaryItemPressed = item =>
+        {
+            selected.Add(item);
+            return false;
+        };
+        cell.Clicked = () => used = true;
+
+        root.OnMouseDown(UiMouseButton.Left, 10, 10);
+
+        Assert.Equal(new uint[] { 0x5001u }, selected);
+        Assert.False(used);
+
+        root.OnMouseUp(UiMouseButton.Left, 10, 10);
+
+        Assert.True(used);
+    }
+
+    [Fact]
+    public void ConsumedPhysicalItemPress_suppressesCompletedActivation()
+    {
+        var (root, list, cell) = RootWithBoundSlot(0x5001u);
+        bool used = false;
+        bool doubleUsed = false;
+        list.PrimaryItemPressed = _ => true;
+        cell.Clicked = () => used = true;
+        cell.DoubleClicked = () => doubleUsed = true;
+
+        root.OnMouseDown(UiMouseButton.Left, 10, 10);
+        root.OnMouseUp(UiMouseButton.Left, 10, 10);
+        root.OnMouseDown(UiMouseButton.Left, 10, 10);
+        root.OnMouseUp(UiMouseButton.Left, 10, 10);
+
+        Assert.False(used);
+        Assert.False(doubleUsed);
+    }
+
+    [Fact]
+    public void ConsumedPhysicalItemPress_cannotPromoteIntoDrag()
+    {
+        var (root, list, _) = RootWithBoundSlot(0x5001u);
+        list.PrimaryItemPressed = _ => true;
+
+        root.OnMouseDown(UiMouseButton.Left, 10, 10);
+        root.OnMouseMove(20, 10);
+
+        Assert.Null(root.DragSource);
+        Assert.Null(root.DragPayload);
+    }
+
     [Fact]
     public void RightClick_withoutDrag_requestsItemListAppraisal()
     {

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

@@ -199,6 +199,20 @@ public sealed class ExternalContainerControllerTests
         Assert.Empty(h.Pickups);
     }
 
+    [Fact]
+    public void MouseDownLoot_selectsBeforeCompletedClick()
+    {
+        using var h = new Harness();
+        h.Open(Chest, new ContainerContentEntry(Item, 0u));
+
+        UiItemSlot cell = h.Contents.GetItem(0)!;
+        cell.OnEvent(new UiEvent(0u, cell, UiEventType.MouseDown));
+
+        Assert.Equal(Item, h.Selection.SelectedObjectId);
+        Assert.True(cell.Selected);
+        Assert.Empty(h.Pickups);
+    }
+
     [Fact]
     public void CloseAndRangeExit_SendUseOnceWithoutNoLongerViewing()
     {

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

@@ -460,7 +460,7 @@ public class InventoryControllerTests
     }
 
     [Fact]
-    public void ClickGridItem_movesSquareOnly_noWire_keepsOpenContainer()
+    public void MouseDownGridItem_movesSquareImmediately_noWire_keepsOpenContainer()
     {
         var (layout, grid, _, top, _, _, _, _) = BuildLayout();
         var objects = new ClientObjectTable();
@@ -468,7 +468,8 @@ public class InventoryControllerTests
         var uses = new List<uint>();
         Bind(layout, objects, uses: uses);
 
-        grid.GetItem(0)!.Clicked!();                           // select the loose item
+        UiItemSlot item = grid.GetItem(0)!;
+        item.OnEvent(new UiEvent(0u, item, UiEventType.MouseDown));
 
         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)
@@ -476,7 +477,7 @@ public class InventoryControllerTests
     }
 
     [Fact]
-    public void ClickGridItem_updatesSharedSelection_andExternalSelectionMovesSquare()
+    public void MouseDownGridItem_updatesSharedSelection_andExternalSelectionMovesSquare()
     {
         var (layout, grid, _, _, _, _, _, _) = BuildLayout();
         var objects = new ClientObjectTable();
@@ -485,7 +486,8 @@ public class InventoryControllerTests
         var selection = new SelectionState();
         Bind(layout, objects, selection: selection);
 
-        grid.GetItem(0)!.Clicked!();
+        UiItemSlot item = grid.GetItem(0)!;
+        item.OnEvent(new UiEvent(0u, item, UiEventType.MouseDown));
 
         Assert.Equal(0xAu, selection.SelectedObjectId);
         Assert.True(grid.GetItem(0)!.Selected);
@@ -555,7 +557,8 @@ public class InventoryControllerTests
             selection: new SelectionState(),
             datFont: null,
             itemInteraction: interaction);
-        grid.GetItem(0)!.Clicked!();
+        UiItemSlot item = grid.GetItem(0)!;
+        item.OnEvent(new UiEvent(0u, item, UiEventType.MouseDown));
         Assert.True(grid.GetItem(0)!.Selected);
 
         Assert.True(interaction.ActivateItem(0xAu));

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

@@ -176,7 +176,7 @@ public class PaperdollControllerTests
     }
 
     [Fact]
-    public void ClickEquippedItem_updatesSharedSelection()
+    public void MouseDownEquippedItem_updatesSharedSelection()
     {
         var (layout, lists) = BuildLayout();
         var objects = new ClientObjectTable();
@@ -184,7 +184,8 @@ public class PaperdollControllerTests
         var selection = new SelectionState();
         Bind(layout, objects, selection: selection);
 
-        lists[HeadSlot].Cell.Clicked!();
+        UiItemSlot cell = lists[HeadSlot].Cell;
+        cell.OnEvent(new UiEvent(0u, cell, UiEventType.MouseDown));
 
         Assert.Equal(0xA01u, selection.SelectedObjectId);
         Assert.True(lists[HeadSlot].Cell.Selected);

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

@@ -192,11 +192,19 @@ public class ToolbarControllerTests
         var shortcuts = new List<ShortcutEntry>
         { new(Index: 0, ObjectId: 0x5001u, SpellId: 0) };
         uint used = 0;
+        var selection = new SelectionState();
 
         ToolbarController.Bind(layout, repo, () => shortcuts,
-            iconIds: (_,_,_,_,_) => 0x77u, useItem: g => used = g);
+            iconIds: (_,_,_,_,_) => 0x77u,
+            useItem: g => used = g,
+            selection: selection);
+        UiItemSlot cell = slots[Row1[0]].Cell;
+        cell.OnEvent(new UiEvent(0u, cell, UiEventType.MouseDown));
+
+        Assert.Equal(0x5001u, selection.SelectedObjectId);
+        Assert.Equal(0u, used);
         // Use now fires on Click (mouse-up), not MouseDown — drag/click disambiguation.
-        slots[Row1[0]].Cell.OnEvent(new UiEvent(0u, null, UiEventType.Click));
+        cell.OnEvent(new UiEvent(0u, cell, UiEventType.Click));
 
         Assert.Equal(0x5001u, used);
     }