Avoid round-trip from view into model

ILSpy/Analyzers/AnalyzerTreeView.cs

@@ -50,26 +50,6 @@ public AnalyzerTreeView()
 			this.BorderThickness = new();
 			this.Root = new AnalyzerRootNode();
 			ContextMenuProvider.Add(this);
-			MessageBus<CurrentAssemblyListChangedEventArgs>.Subscribers += (sender, e) => CurrentAssemblyList_Changed(sender, e);
-		}
-
-
-		void CurrentAssemblyList_Changed(object sender, NotifyCollectionChangedEventArgs e)
-		{
-			if (e.Action == NotifyCollectionChangedAction.Reset)
-			{
-				this.Root.Children.Clear();
-			}
-			else
-			{
-				List<LoadedAssembly> removedAssemblies = new List<LoadedAssembly>();
-				if (e.OldItems != null)
-					removedAssemblies.AddRange(e.OldItems.Cast<LoadedAssembly>());
-				List<LoadedAssembly> addedAssemblies = new List<LoadedAssembly>();
-				if (e.NewItems != null)
-					addedAssemblies.AddRange(e.NewItems.Cast<LoadedAssembly>());
-				((AnalyzerRootNode)this.Root).HandleAssemblyListChanged(removedAssemblies, addedAssemblies);
-			}
 		}
 
 		public void Show()
@@ -144,6 +124,26 @@ public void Analyze(IEntity entity)
 
 		sealed class AnalyzerRootNode : AnalyzerTreeNode
 		{
+			public AnalyzerRootNode()
+			{
+				MessageBus<CurrentAssemblyListChangedEventArgs>.Subscribers += (sender, e) => CurrentAssemblyList_Changed(sender, e);
+			}
+
+			void CurrentAssemblyList_Changed(object sender, NotifyCollectionChangedEventArgs e)
+			{
+				if (e.Action == NotifyCollectionChangedAction.Reset)
+				{
+					this.Children.Clear();
+				}
+				else
+				{
+					var removedAssemblies = e.OldItems?.Cast<LoadedAssembly>().ToArray() ?? [];
+					var addedAssemblies = e.NewItems?.Cast<LoadedAssembly>().ToArray() ?? [];
+
+					HandleAssemblyListChanged(removedAssemblies, addedAssemblies);
+				}
+			}
+
 			public override bool HandleAssemblyListChanged(ICollection<LoadedAssembly> removedAssemblies, ICollection<LoadedAssembly> addedAssemblies)
 			{
 				this.Children.RemoveAll(