diff --git a/UI/ViewModels/HierarchyTreeViewModel.cs b/UI/ViewModels/HierarchyTreeViewModel.cs
index 5a8e03d..6fbc333 100644
--- a/UI/ViewModels/HierarchyTreeViewModel.cs
+++ b/UI/ViewModels/HierarchyTreeViewModel.cs
@@ -8,7 +8,7 @@ using TagHierarchyManager.Models;
 
 namespace TagHierarchyManager.UI.ViewModels;
 
-public partial class HierarchyTreeViewModel : ViewModelBase
+public partial class HierarchyTreeViewModel : ViewModelBase, IDisposable
 {
     private readonly MainWindowViewModel _mainWindow;
     private readonly Dictionary<string, TagItemViewModel> _viewModelMap = new();
@@ -28,11 +28,34 @@ public partial class HierarchyTreeViewModel : ViewModelBase
     {
         this._mainWindow = mainWindow;
         
-        // this is a bit naive, but it works lol
-        this._mainWindow.Database.TagUpdated += (_, _) => Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(OnTreeUpdate);
-        this._mainWindow.Database.TagAdded += (_, _) => Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(OnTreeUpdate);
-        // TODO delete the single tag, don't resync hierarchy. should make it snappier and more manageable.
-        this._mainWindow.Database.TagDeleted += (_, _) => Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(OnTreeUpdate);
+        // TODO proper methods here so it can be unsubscribed.
+        this.SubscribeToEvents();
+    }
+    
+    // TODO unsubscribe, if necessary.
+    private void SubscribeToEvents()
+    {
+        this._mainWindow.Database.TagUpdated += TagDatabase_OnTagUpdated;
+        this._mainWindow.Database.TagAdded += TagDatabase_OnTagAdded;
+        this._mainWindow.Database.TagDeleted += TagDatabase_OnTagDeleted;
+    }
+    
+    private void TagDatabase_OnTagUpdated(object? sender, Tag _) => 
+        Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(OnTreeUpdate);
+
+    private void TagDatabase_OnTagAdded(object? sender, Tag _) => 
+        Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(OnTreeUpdate);
+
+    private void TagDatabase_OnTagDeleted(object? sender, (int id, string name) _) => 
+        Avalonia.Threading.Dispatcher.UIThread.InvokeAsync(OnTreeUpdate);
+
+    public void Dispose()
+    {
+        this._mainWindow.Database.TagUpdated -= TagDatabase_OnTagUpdated;
+        this._mainWindow.Database.TagAdded -= TagDatabase_OnTagAdded;
+        this._mainWindow.Database.TagDeleted -= TagDatabase_OnTagDeleted;
+        
+        _viewModelMap.Clear();
     }
     
     public async Task InitializeAsync()
diff --git a/UI/ViewModels/MainWindowViewModel.cs b/UI/ViewModels/MainWindowViewModel.cs
index 6362d02..cb39e61 100644
--- a/UI/ViewModels/MainWindowViewModel.cs
+++ b/UI/ViewModels/MainWindowViewModel.cs
@@ -147,7 +147,7 @@ public partial class MainWindowViewModel : ViewModelBase
     {
         this.IsDbLoaded = false;
         TagDatabase db = new();
-        db.InitialisationComplete += OnDatabaseLoaded;
+        db.InitialisationComplete += this.TagDatabase_OnInitalisationComplete;
         await db.LoadAsync(filePath);
     }
     
@@ -163,18 +163,20 @@ public partial class MainWindowViewModel : ViewModelBase
         this.UnsavedChanges = false;
     }
     
-    private void OnDatabaseLoaded(object sender, EventArgs e)
+    private void TagDatabase_OnInitalisationComplete(object sender, EventArgs e)
     {
         if (sender is not TagDatabase db) return;
         Avalonia.Threading.Dispatcher.UIThread.Post(async () =>
         {
+            (this.HierarchyTreeViewModel as IDisposable)?.Dispose();
+            
             this.Database = db;
             this.IsDbLoaded = true;
             this.HierarchyTreeViewModel = new HierarchyTreeViewModel(this);
             await this.HierarchyTreeViewModel.InitializeAsync();
             this.OnPropertyChanged(nameof(TotalTags));
             this.OnPropertyChanged(nameof(WindowTitle));
-            this.Database.InitialisationComplete -= OnDatabaseLoaded;
+            this.Database.InitialisationComplete -= this.TagDatabase_OnInitalisationComplete;
             this.StatusBlockText = string.Format(Resources.StatusBlockDbLoadSuccessful, this.Database.Name);
         });
         Debug.WriteLine($"Database loaded on UI - name: {db.Name}, version: {db.Version}");