diff --git a/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs b/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs
index 296a1059..efa69730 100644
--- a/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs
+++ b/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs
@@ -484,6 +484,36 @@ public class InventoryControllerTests
         Assert.Equal(Player, objects.Get(0xAu)!.ContainerId);   // NOT removed on lift (unlike the toolbar)
     }
 
+    [Fact]
+    public void OnDragOver_closedBag_unknownCount_advisoryAccepts() // AP-61
+    {
+        var (layout, _, containers, _, _, _, _, _) = BuildLayout();
+        var objects = new ClientObjectTable();
+        SeedBag(objects, 0xC, slot: 0, itemsCapacity: 24);     // a bag with capacity but NO indexed contents (closed)
+        objects.AddOrUpdate(new ClientObject { ObjectId = 0xFFFFu });
+        var ctrl = (IItemListDragHandler)Bind(layout, objects);
+
+        // GetContents(0xC) is empty (a closed bag's contents aren't indexed until opened) → not known-full → accept.
+        Assert.True(ctrl.OnDragOver(containers, containers.GetItem(0)!, Payload(0xFFFFu)));
+    }
+
+    [Fact]
+    public void Drop_thenServerRollback_revertsTheMove() // optimistic + InventoryServerSaveFailed snap-back
+    {
+        var (layout, _, containers, _, _, _, _, _) = BuildLayout();
+        var objects = new ClientObjectTable();
+        SeedContained(objects, 0xA, Player, slot: 3);          // item starts in the main pack at slot 3
+        SeedBag(objects, 0xC, slot: 0, itemsCapacity: 24);
+        var ctrl = Bind(layout, objects);
+
+        ((IItemListDragHandler)ctrl).HandleDropRelease(containers, containers.GetItem(0)!, Payload(0xAu));
+        Assert.Equal(0xCu, objects.Get(0xAu)!.ContainerId);    // moved into the bag optimistically (instant)
+
+        objects.RollbackMove(0xAu);                            // server rejected (InventoryServerSaveFailed)
+        Assert.Equal(Player, objects.Get(0xAu)!.ContainerId);  // snapped back to the main pack
+        Assert.Equal(3, objects.Get(0xAu)!.ContainerSlot);     // and the original slot
+    }
+
     // Reads the text of the UiText caption child attached by the controller.
     private static string CaptionText(UiElement host)
     {
diff --git a/tests/AcDream.Core.Net.Tests/GameEventWiringTests.cs b/tests/AcDream.Core.Net.Tests/GameEventWiringTests.cs
index 92d7b471..ae191438 100644
--- a/tests/AcDream.Core.Net.Tests/GameEventWiringTests.cs
+++ b/tests/AcDream.Core.Net.Tests/GameEventWiringTests.cs
@@ -606,6 +606,28 @@ public sealed class GameEventWiringTests
         Assert.Equal(2, items.Get(0x50000B01u)!.ContainerSlot);
     }
 
+    [Fact]
+    public void WireAll_InventoryPutObjInContainer_ConfirmsOptimisticMove_soNoRollback()
+    {
+        var (d, items, _, _, _) = MakeAll();
+        items.RecordMembership(0x50000B02u, containerId: 0x500000C0u);
+        items.MoveItem(0x50000B02u, 0x500000C0u, 2);
+        items.MoveItemOptimistic(0x50000B02u, 0x500000C1u, 0);            // optimistic move (pending snapshot)
+
+        // Server CONFIRMS via InventoryPutObjInContainer (item, container, placement, containerType).
+        byte[] payload = new byte[16];
+        BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(0), 0x50000B02u);
+        BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(4), 0x500000C1u);
+        BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(8), 0u);   // placement
+        BinaryPrimitives.WriteUInt32LittleEndian(payload.AsSpan(12), 0u);  // containerType
+        var env = GameEventEnvelope.TryParse(WrapEnvelope(GameEventType.InventoryPutObjInContainer, payload));
+        d.Dispatch(env!.Value);
+
+        // ConfirmMove cleared the pending snapshot → a later rollback is a no-op (the move stuck).
+        Assert.False(items.RollbackMove(0x50000B02u));
+        Assert.Equal(0x500000C1u, items.Get(0x50000B02u)!.ContainerId);
+    }
+
     [Fact]
     public void WireAll_InventoryPutObjectIn3D_UnparentsFromContainer()
     {