diff --git a/src/AcDream.App/UI/Layout/InventoryController.cs b/src/AcDream.App/UI/Layout/InventoryController.cs
index 9aa6ac45..01de0aea 100644
--- a/src/AcDream.App/UI/Layout/InventoryController.cs
+++ b/src/AcDream.App/UI/Layout/InventoryController.cs
@@ -33,7 +33,9 @@ public sealed class InventoryController
 
     // 3D-items grid: 192x96 → 6 cols x 3 rows of the 32x32 UIItem cell (template 0x21000037).
     private const int   ContentsColumns = 6;
-    private const float CellPx = 32f;
+    private const float ContentsCellPx = 32f;   // gm3DItemsUI grid (192x96 = 6x3 of 32px)
+    private const float BackpackCellPx = 36f;   // gmBackpackUI column cells (0x100001C9/CA = 36px)
+    private const int   SideBagSlots   = 7;     // 0x100001CA is 36x252 = 7 slots
 
     private readonly ClientObjectTable _objects;
     private readonly Func<uint> _playerGuid;
@@ -73,8 +75,8 @@ public sealed class InventoryController
         if (_contentsGrid is not null)
         {
             _contentsGrid.Columns    = ContentsColumns;
-            _contentsGrid.CellWidth  = CellPx;
-            _contentsGrid.CellHeight = CellPx;
+            _contentsGrid.CellWidth  = ContentsCellPx;
+            _contentsGrid.CellHeight = ContentsCellPx;
         }
 
         // Bind the gutter scrollbar to the contents grid's scroll model (the factory built
@@ -94,8 +96,8 @@ public sealed class InventoryController
         if (_containerList is not null)
         {
             _containerList.Columns    = 1;
-            _containerList.CellWidth  = CellPx;
-            _containerList.CellHeight = CellPx;
+            _containerList.CellWidth  = BackpackCellPx;
+            _containerList.CellHeight = BackpackCellPx;
         }
 
         // Burden meter: vertical 11×58 bar (gmBackpackUI m_burdenMeter, retail direction 4).
@@ -177,6 +179,21 @@ public sealed class InventoryController
             list.AddItem(cell);
         }
 
+        // Side-bag column: pad with empty slot frames up to the player's container capacity
+        // (clamped to the 7-slot column) so it reads like retail (bags on top, empty frames
+        // below) rather than one lone cell. Falls back to the full 7 slots when capacity is
+        // unknown (divergence AP-52).
+        if (_containerList is not null)
+        {
+            int capacity = _objects.Get(p)?.ContainersCapacity ?? 0;
+            int bags = _containerList.GetNumUIItems();
+            int slots = capacity > 0 ? capacity : SideBagSlots;
+            slots = Math.Max(slots, bags);
+            slots = Math.Min(slots, SideBagSlots);
+            while (_containerList.GetNumUIItems() < slots)
+                _containerList.AddItem(new UiItemSlot { SpriteResolve = _containerList.SpriteResolve });
+        }
+
         // Main-pack cell: the player's own container. Icon = placeholder until a backpack
         // RenderSurface DID is pinned (spec §3 / divergence row). Bind the guid so a future
         // click can select it.
diff --git a/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs b/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs
index 53844cd5..0fa5d270 100644
--- a/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs
+++ b/tests/AcDream.App.Tests/UI/Layout/InventoryControllerTests.cs
@@ -83,8 +83,9 @@ public class InventoryControllerTests
         Assert.Equal(2, grid.GetNumUIItems());          // 2 loose
         Assert.Equal(0xAu, grid.GetItem(0)!.ItemId);
         Assert.Equal(0xBu, grid.GetItem(1)!.ItemId);
-        Assert.Equal(1, containers.GetNumUIItems());     // 1 side bag
+        Assert.Equal(7, containers.GetNumUIItems());     // 1 side bag + 6 empty (no capacity → 7-slot column)
         Assert.Equal(0xCu, containers.GetItem(0)!.ItemId);
+        Assert.Equal(0u, containers.GetItem(1)!.ItemId); // padded empty frame
     }
 
     [Fact]
@@ -102,7 +103,8 @@ public class InventoryControllerTests
 
         Assert.Equal(1, grid.GetNumUIItems());          // only the loose item
         Assert.Equal(0xAu, grid.GetItem(0)!.ItemId);
-        Assert.Equal(0, containers.GetNumUIItems());    // equipped item is not a side bag either
+        Assert.Equal(7, containers.GetNumUIItems());    // 7 empty slots (no bags; the equipped item isn't here)
+        Assert.Equal(0u, containers.GetItem(0)!.ItemId);
     }
 
     [Fact]
@@ -203,6 +205,22 @@ public class InventoryControllerTests
         Assert.Same(grid.Scroll, bar.Model);            // the bar drives the grid's scroll
     }
 
+    [Fact]
+    public void Side_bag_column_pads_empty_slots_up_to_capacity()
+    {
+        var (layout, _, containers, _, _, _, _, _) = BuildLayout();
+        var objects = new ClientObjectTable();
+        objects.AddOrUpdate(new ClientObject { ObjectId = Player, ContainersCapacity = 3 });
+        SeedContained(objects, 0xC, Player, slot: 0, type: ItemType.Container);  // one side bag
+
+        Bind(layout, objects);
+
+        Assert.Equal(3, containers.GetNumUIItems());        // 1 bag + 2 empty = capacity 3
+        Assert.Equal(0xCu, containers.GetItem(0)!.ItemId);  // the bag
+        Assert.Equal(0u,  containers.GetItem(1)!.ItemId);   // empty frame
+        Assert.Equal(0u,  containers.GetItem(2)!.ItemId);   // empty frame
+    }
+
     // Reads the text of the UiText caption child attached by the controller.
     private static string CaptionText(UiElement host)
     {