diff --git a/ILSpy.Tests/AssemblyList/AssemblyTreeTests.cs b/ILSpy.Tests/AssemblyList/AssemblyTreeTests.cs
index ff31e320a..a79a9c76c 100644
--- a/ILSpy.Tests/AssemblyList/AssemblyTreeTests.cs
+++ b/ILSpy.Tests/AssemblyList/AssemblyTreeTests.cs
@@ -975,6 +975,8 @@ public class AssemblyTreeTests
 		grid.Focus();
 		Dispatcher.UIThread.RunJobs();
 
+		int itemsBefore = (grid.ItemsSource as System.Collections.ICollection)?.Count ?? -1;
+
 		// Act — headless keyboard event simulating the user pressing Del while the tree has
 		// focus.
 		global::Avalonia.Headless.HeadlessWindowExtensions.KeyPress(
@@ -984,7 +986,11 @@ public class AssemblyTreeTests
 			global::Avalonia.Input.PhysicalKey.Delete,
 			null);
 
-		// Assert — the sacrificial assembly is gone from the list; the survivor remains.
+		// Assert — the sacrificial assembly is gone from the data list AND the grid's bound
+		// ItemsSource drops by one. Both halves matter: a passing AssemblyList assertion alone
+		// would mask regressions where the data updates but the grid stays bound to a stale
+		// snapshot (which is exactly what happened when the BindTree filter materialised the
+		// children into a List instead of forwarding the live ObservableCollection).
 		await Waiters.WaitForAsync(() =>
 			!vm.AssemblyTreeModel.AssemblyList!.GetAssemblies()
 				.Any(a => string.Equals(a.ShortName, sacrificialName, System.StringComparison.Ordinal)));
@@ -992,6 +998,10 @@ public class AssemblyTreeTests
 		vm.AssemblyTreeModel.AssemblyList!.GetAssemblies()
 			.Should().Contain(a => a.ShortName == survivorName,
 				"only the selected assembly should be removed");
+
+		await Waiters.WaitForAsync(
+			() => (grid.ItemsSource as System.Collections.ICollection)?.Count < itemsBefore,
+			description: "DataGrid item count should drop after the assembly is unloaded");
 	}
 
 	[AvaloniaTest]
diff --git a/ILSpy/AssemblyTree/AssemblyListPane.axaml.cs b/ILSpy/AssemblyTree/AssemblyListPane.axaml.cs
index 54d71a4a9..3c05268d3 100644
--- a/ILSpy/AssemblyTree/AssemblyListPane.axaml.cs
+++ b/ILSpy/AssemblyTree/AssemblyListPane.axaml.cs
@@ -352,10 +352,10 @@ namespace ILSpy.AssemblyTree
 			}
 		}
 
-		// Apply the active LanguageSettings filter (if any). Returns the children unfiltered when
-		// no settings are available (design-time / unit-host scenarios) so the tree still
-		// renders. Materialises into a List so each call returns a stable snapshot the grid
-		// can iterate twice without re-evaluating.
+		// Apply the active LanguageSettings filter to a child collection materialised on
+		// expansion. Returns a fresh List so iteration is stable; live updates at deeper levels
+		// are not preserved (members are realised once per expansion — adds/removes mid-expand
+		// don't happen in practice).
 		static IEnumerable<SharpTreeNode> FilterChildren(IEnumerable<SharpTreeNode> children, LanguageSettings? settings)
 		{
 			if (settings == null)
@@ -383,7 +383,11 @@ namespace ILSpy.AssemblyTree
 			};
 
 			var hierarchicalModel = new HierarchicalModel<SharpTreeNode>(options);
-			hierarchicalModel.SetRoots(FilterChildren(root.Children, settings));
+			// Pass the live ObservableCollection at the root so the grid observes
+			// CollectionChanged when assemblies are unloaded / opened. Filter is not applied
+			// at this level (AssemblyTreeNode never reports Hidden); deeper levels filter
+			// on expansion via ChildrenSelector.
+			hierarchicalModel.SetRoots(root.Children);
 
 			TreeGrid.HierarchicalModel = hierarchicalModel;
 		}