fix(vendor): gate-findings pass — the X button HIDES like retail, clicks return, the dropdown scrolls, pyreal suffix, staged-tab slots

The user's connected gate found five issues; each fixed at the root:

G4 (the discovery): retail's vendor X button calls only SetVisible(0)
(pc:204147-204182) — the SESSION stays open and re-using the vendor
lands on the same-session refresh; the range watcher remains the sole
real close. Our port invented a full teardown on X, which is exactly
why reopening died. The Runtime fixture proves the wire dispatch was
never the problem; ACE has no already-open short-circuit.

G3 (regression from the drag-suppression fix): denying IsDragSource
also dropped press capture, so clicks fell through to window-drag.
UiItemSlot.HandlesClick now claims presses for any occupied cell
independent of drag eligibility — clickable and draggable are separate
concerns.

G5: the authored popup 0x21000043 is ONE scrollable column with a real
scrollbar subtree (live-dat scan: ListBox 0x10000350 + scrollbar
0x10000351), not a 3x6 grid. UiMenu gains an authored-driven
Scrollable mode (wheel, thumb drag, track paging, up/down buttons);
chat's menu is untouched and its ten tests prove it.

G1: retail's cost format is "%s %hsp (you have %hsp)" — the p after
each %hs is a LITERAL pyreal suffix the port swallowed as part of the
specifier. Restored.

G2: the Buying/Selling pages' authored lists (same cell template as
Items) get the empty-slot fill, presentation-only until staging.

Clean-room complete solution: 11,390 passed / 4 skipped / 0 failed.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

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

@@ -70,6 +70,82 @@ public sealed class VendorUiControllerTests
         Assert.NotNull(controller);
     }
 
+    [Fact]
+    public void Bind_FromRealDatFixture_BuyingAndSellingLists_ConfiguredForEmptySlotFill()
+    {
+        // G2 (vendor gate finding): the Buying/Selling pages' item strips
+        // never got the empty-slot fill the Items list has, so they showed
+        // the bare authored blue background instead. This proves the real
+        // LayoutDesc 0x21000012 fixture's 0x100000C5 (Buying list)/0x100000CE
+        // (Selling list) resolve to real UiItemList widgets and come out of
+        // Bind configured identically to the Items strip (F7b) — same
+        // single-row/horizontal-scroll/cell-size shape, fill enabled, a
+        // non-drag-source empty-slot factory wired, and the sibling
+        // scrollbar bound to the SAME list's scroll model. The lists stay
+        // UNPOPULATED (no AddItem call anywhere in this path) — staging is
+        // still deferred.
+        ImportedLayout layout = FixtureLoader.LoadVendor();
+        var screen = new UiRoot { Width = 1280f, Height = 800f };
+        RetailWindowHandle window = RetailWindowFrame.Mount(
+            screen,
+            layout.Root,
+            static _ => (0u, 0, 0),
+            new RetailWindowFrame.Options
+            {
+                WindowName = "vendor-fixture-smoke-2",
+                Chrome = RetailWindowChrome.Imported,
+                Visible = false,
+            });
+
+        var objects = new ClientObjectTable();
+        using var itemInteraction = new ItemInteractionController(
+            objects,
+            new RuntimeInteractionTransactionState(new InventoryTransactionState(objects)),
+            new InteractionState(),
+            playerGuid: static () => 0u,
+            sendUse: null,
+            sendUseWithTarget: null,
+            sendWield: null,
+            sendDrop: null);
+        VendorUiController? controller = VendorUiController.Bind(
+            layout,
+            new VendorState(),
+            window,
+            static (_, _, _, _, _) => 0u,
+            objects,
+            static () => 0u,
+            itemInteraction,
+            new SelectionState(),
+            new StackSplitQuantityState(),
+            datFont: null,
+            debugFont: null,
+            static _ => (0u, 0, 0));
+        Assert.NotNull(controller);
+
+        var buyingList = Assert.IsType<UiItemList>(layout.FindElement(VendorUiController.BuyingListId));
+        var sellingList = Assert.IsType<UiItemList>(layout.FindElement(VendorUiController.SellingListId));
+        var buyingScrollbar = Assert.IsType<UiScrollbar>(
+            layout.FindElement(VendorUiController.BuyingScrollbarId));
+        var sellingScrollbar = Assert.IsType<UiScrollbar>(
+            layout.FindElement(VendorUiController.SellingScrollbarId));
+
+        foreach (UiItemList list in new[] { buyingList, sellingList })
+        {
+            Assert.True(list.SingleRow);
+            Assert.True(list.HorizontalScroll);
+            Assert.Equal(32f, list.CellWidth);
+            Assert.Equal(32f, list.CellHeight);
+            Assert.True(list.FillVisibleEmptySlots);
+            Assert.NotNull(list.EmptySlotFactory);
+            Assert.Equal(0, list.GetNumUIItems()); // never populated
+        }
+
+        Assert.Same(buyingList.Scroll, buyingScrollbar.Model);
+        Assert.True(buyingScrollbar.Horizontal);
+        Assert.Same(sellingList.Scroll, sellingScrollbar.Model);
+        Assert.True(sellingScrollbar.Horizontal);
+    }
+
     private sealed class Harness
     {
         // F2/F3: a deterministic non-zero player coin total so the cost-text
@@ -310,7 +386,7 @@ public sealed class VendorUiControllerTests
         // to the singular name UNCHANGED (not an invented "Arrows" + "s").
         Assert.Equal("100 Arrows", GetText(h.ItemNameText));
         Assert.Equal(
-            $"cost {2000:N0} (you have {Harness.DefaultPlayerCoinValue:N0})",
+            $"cost {2000:N0}p (you have {Harness.DefaultPlayerCoinValue:N0}p)",
             GetText(h.ItemCostText));
     }
 
@@ -338,7 +414,7 @@ public sealed class VendorUiControllerTests
 
         Assert.Equal("Bread", GetText(h.ItemNameText));
         Assert.Equal(
-            $"costs {20:N0} (you have {Harness.DefaultPlayerCoinValue:N0})",
+            $"costs {20:N0}p (you have {Harness.DefaultPlayerCoinValue:N0}p)",
             GetText(h.ItemCostText));
     }
 
@@ -386,7 +462,7 @@ public sealed class VendorUiControllerTests
         // selection.
         Assert.Equal("Arrows", GetText(h.ItemNameText));
         Assert.Equal(
-            $"costs {20:N0} (you have {Harness.DefaultPlayerCoinValue:N0})",
+            $"costs {20:N0}p (you have {Harness.DefaultPlayerCoinValue:N0}p)",
             GetText(h.ItemCostText));
 
         // Player drags the slider to 40 AFTER selecting -- no re-click, no
@@ -396,7 +472,7 @@ public sealed class VendorUiControllerTests
         // SellPrice = ceil(2.0*10*40 - 0.1) = 800.
         Assert.Equal("40 Arrows", GetText(h.ItemNameText));
         Assert.Equal(
-            $"cost {800:N0} (you have {Harness.DefaultPlayerCoinValue:N0})",
+            $"cost {800:N0}p (you have {Harness.DefaultPlayerCoinValue:N0}p)",
             GetText(h.ItemCostText));
 
         h.BuyButton.OnClick!.Invoke();
@@ -576,6 +652,45 @@ public sealed class VendorUiControllerTests
         Assert.NotEqual(0u, cell.ItemId); // occupied -- would otherwise be a drag source by default
         Assert.False(cell.IsDragSource);
         Assert.Null(cell.GetDragPayload());
+        // G3 (vendor gate finding): a row must still CAPTURE its own press
+        // even though it never mints a drag payload -- see
+        // UiItemSlot.HandlesClick and the real-event-path test below.
+        Assert.True(cell.HandlesClick);
+    }
+
+    [Fact]
+    public void ShopRow_ClickEvent_SelectsItem_DespiteNotBeingADragSource()
+    {
+        // G3 (vendor gate finding): the F3 drag-suppression fix
+        // (AllowDragSource=false) left occupied vendor rows with
+        // IsDragSource==false -- before the G3 fix that meant UiRoot's
+        // mousedown dispatch found no reason to claim the press at all, so
+        // it fell through to the window-move fallback (hover showed the
+        // move-window cursor; a press dragged the whole panel instead of
+        // selecting a row). This drives the REAL UiItemSlot.OnEvent state
+        // machine (MouseDown then Click), the same sequence UiRoot's
+        // dispatch produces, rather than invoking the wired Clicked
+        // delegate directly -- proving the row still completes a press then
+        // click and drives selection.
+        const uint SecondArmorGuid = 0x60000110u;
+        var h = new Harness();
+        h.State.Apply(VendorGuid, Profile(), new[]
+        {
+            new VendorShopItem(ArmorItemGuid, -1, 2u, "Chainmail", (uint)ItemType.Armor, 200u, 500),
+            new VendorShopItem(SecondArmorGuid, -1, 4u, "Buckler", (uint)ItemType.Armor, 900u, 40),
+        });
+        Assert.Equal(ArmorItemGuid, h.Selection.SelectedObjectId); // auto-selected first
+
+        UiItemSlot secondCell = h.ItemList.GetItem(1)!;
+        Assert.Equal(SecondArmorGuid, secondCell.ItemId);
+        Assert.False(secondCell.IsDragSource);   // never a drag source (F3)
+        Assert.True(secondCell.HandlesClick);    // but still claims its own press (G3)
+
+        secondCell.OnEvent(new UiEvent(0u, secondCell, UiEventType.MouseDown));
+        secondCell.OnEvent(new UiEvent(0u, secondCell, UiEventType.Click));
+
+        Assert.Equal(SecondArmorGuid, h.Selection.SelectedObjectId);
+        Assert.True(secondCell.Selected);
     }
 
     [Fact]
@@ -720,8 +835,22 @@ public sealed class VendorUiControllerTests
     }
 
     [Fact]
-    public void CloseButton_RoutesThroughVendorStateClose_NotADirectFieldWrite()
+    public void CloseButton_HidesTheWindowOnly_LeavesTheSessionOpenForARefreshInPlaceReopen()
     {
+        // G4 (vendor gate finding): retail's close/pushpin button —
+        // gmVendorUI::HandleButtonClicks's 0x100000d6 case (pc:204147-204182)
+        // — with nothing staged in the Buying/Selling lists (this port never
+        // stages anything; Slice 6 territory) calls ONLY SetVisible(0),
+        // never gmVendorUI::CloseVendor (pc:202080, the range-watcher-
+        // unregister/session-teardown function VendorState.Close ports).
+        // The OLD port called VendorState.Close() directly from this button
+        // — an over-eager full teardown retail does not perform on an
+        // ordinary close. RuntimeVendorRangeQuery.EnforceRange (evaluated
+        // every frame regardless of window visibility) remains the sole
+        // path to a full close once the player actually leaves UseRadius —
+        // see Closed_HidesWindowAndClearsListAndText for that path,
+        // unaffected by this change since it calls VendorState.Close()
+        // directly rather than through this button.
         var h = new Harness();
         h.State.Apply(VendorGuid, Profile(), new[]
         {
@@ -730,12 +859,25 @@ public sealed class VendorUiControllerTests
 
         h.CloseButton.OnClick!.Invoke();
 
-        // The panel never mutates VendorState directly — the ONLY path from
-        // the close button to a cleared session is VendorState.Close()
-        // itself, so VendorId reads back 0 through the owner's own public
-        // surface, not a private field poke.
-        Assert.Equal(0u, h.State.VendorId);
         Assert.False(h.Window.IsVisible);
+        // Unlike the OLD port, the session itself is NOT torn down — the
+        // owner still reports the same open vendor in the background,
+        // matching retail's hidden-but-still-registered range watcher.
+        Assert.Equal(VendorGuid, h.State.VendorId);
+
+        // Re-approaching the SAME vendor (e.g. pressing Use again while
+        // still in range) now reaches retail's sameVendor==1 refresh-in-
+        // place path (VendorStateTransitionKind.Refreshed) instead of a
+        // from-scratch Opened, and reopens the window.
+        var kinds = new List<VendorStateTransitionKind>();
+        h.State.Changed += t => kinds.Add(t.Kind);
+        h.State.Apply(VendorGuid, Profile(), new[]
+        {
+            new VendorShopItem(ArmorItemGuid, -1, 2u, "Chainmail", (uint)ItemType.Armor, 200u, 500),
+        });
+
+        Assert.True(h.Window.IsVisible);
+        Assert.Equal([VendorStateTransitionKind.Refreshed], kinds);
     }
 
     [Fact]