diff --git a/Source/Collections/AsyncVirtualObservableReadOnlyList.cs b/Source/Collections/AsyncVirtualObservableReadOnlyList.cs
index cc4781e..2871bdd 100644
--- a/Source/Collections/AsyncVirtualObservableReadOnlyList.cs
+++ b/Source/Collections/AsyncVirtualObservableReadOnlyList.cs
@@ -289,7 +289,19 @@ namespace Nuclex.Avalonia.Collections {
     /// <param name="item">Item whose index will be determined</param>
     /// <returns>The index of the item in the list or -1 if not found</returns>
     public int IndexOf(TItem item) {
-      return this.typedList.IndexOf(item);
+      requireCount();
+      requireAllPages();
+
+      // TODO: this won't work, it will compare the placeholder items :-/
+
+      IComparer<TItem> itemComparer = Comparer<TItem>.Default;
+      for(int index = 0; index < this.assumedCount.Value; ++index) {
+        if(itemComparer.Compare(this.typedList[index], item) == 0) {
+          return index;
+        }
+      }
+
+      return -1;
     }
 
     /// <summary>Inserts an item into the list at the specified index</summary>
@@ -344,10 +356,8 @@ namespace Nuclex.Avalonia.Collections {
     /// <param name="item">Item the list will be checked for</param>
     /// <returns>True if the list contains the specified items</returns>
     public bool Contains(TItem item) {
-      requireCount();
-      requireAllPages();
-
-      return this.typedList.Contains(item);
+      // TODO: this won't work, it will compare the placeholder items :-/
+      return (IndexOf(item) != -1);
     }
 
     /// <summary>Copies the contents of the list into an array</summary>
@@ -359,14 +369,13 @@ namespace Nuclex.Avalonia.Collections {
       requireCount();
       requireAllPages();
 
+      // TODO: this won't work, it will copy the placeholder items :-/
       this.typedList.CopyTo(array, arrayIndex);
     }
 
     /// <summary>Total number of items in the list</summary>
     public int Count {
-      get {
-        return requireCount();
-      }
+      get { return requireCount(); }
     }
 
     /// <summary>Whether the list is a read-only list</summary>
diff --git a/Source/IActiveWindowTracker.cs b/Source/IActiveWindowTracker.cs
index 82d341c..ecb899d 100644
--- a/Source/IActiveWindowTracker.cs
+++ b/Source/IActiveWindowTracker.cs
@@ -1,35 +1,35 @@
-#region Apache License 2.0
-/*
-Nuclex Foundation libraries for .NET
-Copyright (C) 2002-2025 Markus Ewald / Nuclex Development Labs
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-#endregion // Apache License 2.0
-
-using System;
-
-using Avalonia.Controls;
-
-namespace Nuclex.Avalonia {
-
-  /// <summary>Allows the currently active top level window to be looked up</summary>
-  public interface IActiveWindowTracker {
-
-    /// <summary>The currently active top-level or modal window</summary>
-    Window? ActiveWindow { get; }
-
-  }
-
-} // namespace Nuclex.Avalonia
-
+#region Apache License 2.0
+/*
+Nuclex Foundation libraries for .NET
+Copyright (C) 2002-2025 Markus Ewald / Nuclex Development Labs
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+#endregion // Apache License 2.0
+
+using System;
+
+using Avalonia.Controls;
+
+namespace Nuclex.Avalonia {
+
+  /// <summary>Allows the currently active top level window to be looked up</summary>
+  public interface IActiveWindowTracker {
+
+    /// <summary>The currently active top-level or modal window</summary>
+    Window? ActiveWindow { get; }
+
+  }
+
+} // namespace Nuclex.Avalonia
+
diff --git a/Source/IWindowManager.cs b/Source/IWindowManager.cs
index e050f52..d68ed93 100644
--- a/Source/IWindowManager.cs
+++ b/Source/IWindowManager.cs
@@ -1,114 +1,114 @@
-#region Apache License 2.0
-/*
-Nuclex Foundation libraries for .NET
-Copyright (C) 2002-2025 Markus Ewald / Nuclex Development Labs
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-#endregion // Apache License 2.0
-
-using System;
-using System.Threading.Tasks;
-
-using Avalonia.Controls;
-
-namespace Nuclex.Avalonia {
-
-  /// <summary>Manages open windows and connecting them to view models</summary>
-  public interface IWindowManager : IActiveWindowTracker {
-
-    /// <summary>Opens a view as a new root window of the application</summary>
-    /// <typeparam name="TViewModel">
-    ///   Type of view model a root window will be opened for
-    /// </typeparam>
-    /// <param name="viewModel">
-    ///   View model a window will be opened for. If null, the view model will be
-    ///   created as well (unless the dialog already specifies one as a resource)
-    /// </param>
-    /// <param name="disposeOnClose">
-    ///   Whether the view model should be disposed when the view is closed
-    /// </param>
-    /// <returns>The window that has been opened by the window manager</returns>
-    Window OpenRoot<TViewModel>(
-      TViewModel? viewModel = null, bool disposeOnClose = true
-    ) where TViewModel : class;
-
-    /// <summary>Displays a view as a modal window</summary>
-    /// <typeparam name="TViewModel">
-    ///   Type of the view model for which a view will be displayed
-    /// </typeparam>
-    /// <param name="viewModel">
-    ///   View model a modal window will be displayed for. If null, the view model will
-    ///   be created as well (unless the dialog already specifies one as a resource)
-    /// </param>
-    /// <param name="disposeOnClose">
-    ///   Whether the view model should be disposed when the view is closed
-    /// </param>
-    /// <returns>The return value of the modal window</returns>
-    Task ShowModalAsync<TViewModel>(
-      TViewModel? viewModel = null, bool disposeOnClose = false
-    ) where TViewModel : class;
-
-    /// <summary>Displays a view as a modal window</summary>
-    /// <typeparam name="TResult">
-    ///   Type of result the modal dialog will return to the caller
-    /// </typeparam>
-    /// <typeparam name="TViewModel">
-    ///   Type of the view model for which a view will be displayed
-    /// </typeparam>
-    /// <param name="viewModel">
-    ///   View model a modal window will be displayed for. If null, the view model will
-    ///   be created as well (unless the dialog already specifies one as a resource)
-    /// </param>
-    /// <param name="disposeOnClose">
-    ///   Whether the view model should be disposed when the view is closed
-    /// </param>
-    /// <returns>The return value of the modal window</returns>
-    Task<TResult> ShowModalAsync<TResult, TViewModel>(
-      TViewModel? viewModel = null, bool disposeOnClose = true
-    ) where TViewModel : class;
-
-    /// <summary>Creates the view for the specified view model</summary>
-    /// <typeparam name="TViewModel">
-    ///   Type of view model for which a view will be created
-    /// </typeparam>
-    /// <param name="viewModel">
-    ///   View model a view will be created for. If null, the view model will be
-    ///   created as well (unless the dialog already specifies one as a resource)
-    /// </param>
-    /// <returns>The view for the specified view model</returns>
-    Control CreateView<TViewModel>(TViewModel? viewModel = null)
-      where TViewModel : class;
-
-    /// <summary>Creates a view model without a matching view</summary>
-    /// <typeparam name="TViewModel">Type of view model that will be created</typeparam>
-    /// <returns>The new view model</returns>
-    /// <remarks>
-    ///   <para>
-    ///     This is useful if a view model needs to create child view models (i.e. paged container
-    ///     and wants to ensure the same dependency injector (if any) if used as the window
-    ///     manager uses for other view models it creates.
-    ///   </para>
-    ///   <para>
-    ///     This way, view models can set up their child view models without having to immediately
-    ///     bind a view to them. Later on, views can use the window manager to create a matching
-    ///     child view and store it in a container.
-    ///   </para>
-    /// </remarks>
-    TViewModel CreateViewModel<TViewModel>()
-      where TViewModel : class;
-
-  }
-
-} // namespace Nuclex.Avalonia
-
+#region Apache License 2.0
+/*
+Nuclex Foundation libraries for .NET
+Copyright (C) 2002-2025 Markus Ewald / Nuclex Development Labs
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+#endregion // Apache License 2.0
+
+using System;
+using System.Threading.Tasks;
+
+using Avalonia.Controls;
+
+namespace Nuclex.Avalonia {
+
+  /// <summary>Manages open windows and connecting them to view models</summary>
+  public interface IWindowManager : IActiveWindowTracker {
+
+    /// <summary>Opens a view as a new root window of the application</summary>
+    /// <typeparam name="TViewModel">
+    ///   Type of view model a root window will be opened for
+    /// </typeparam>
+    /// <param name="viewModel">
+    ///   View model a window will be opened for. If null, the view model will be
+    ///   created as well (unless the dialog already specifies one as a resource)
+    /// </param>
+    /// <param name="disposeOnClose">
+    ///   Whether the view model should be disposed when the view is closed
+    /// </param>
+    /// <returns>The window that has been opened by the window manager</returns>
+    Window OpenRoot<TViewModel>(
+      TViewModel? viewModel = null, bool disposeOnClose = true
+    ) where TViewModel : class;
+
+    /// <summary>Displays a view as a modal window</summary>
+    /// <typeparam name="TViewModel">
+    ///   Type of the view model for which a view will be displayed
+    /// </typeparam>
+    /// <param name="viewModel">
+    ///   View model a modal window will be displayed for. If null, the view model will
+    ///   be created as well (unless the dialog already specifies one as a resource)
+    /// </param>
+    /// <param name="disposeOnClose">
+    ///   Whether the view model should be disposed when the view is closed
+    /// </param>
+    /// <returns>The return value of the modal window</returns>
+    Task ShowModalAsync<TViewModel>(
+      TViewModel? viewModel = null, bool disposeOnClose = false
+    ) where TViewModel : class;
+
+    /// <summary>Displays a view as a modal window</summary>
+    /// <typeparam name="TResult">
+    ///   Type of result the modal dialog will return to the caller
+    /// </typeparam>
+    /// <typeparam name="TViewModel">
+    ///   Type of the view model for which a view will be displayed
+    /// </typeparam>
+    /// <param name="viewModel">
+    ///   View model a modal window will be displayed for. If null, the view model will
+    ///   be created as well (unless the dialog already specifies one as a resource)
+    /// </param>
+    /// <param name="disposeOnClose">
+    ///   Whether the view model should be disposed when the view is closed
+    /// </param>
+    /// <returns>The return value of the modal window</returns>
+    Task<TResult> ShowModalAsync<TResult, TViewModel>(
+      TViewModel? viewModel = null, bool disposeOnClose = true
+    ) where TViewModel : class;
+
+    /// <summary>Creates the view for the specified view model</summary>
+    /// <typeparam name="TViewModel">
+    ///   Type of view model for which a view will be created
+    /// </typeparam>
+    /// <param name="viewModel">
+    ///   View model a view will be created for. If null, the view model will be
+    ///   created as well (unless the dialog already specifies one as a resource)
+    /// </param>
+    /// <returns>The view for the specified view model</returns>
+    Control CreateView<TViewModel>(TViewModel? viewModel = null)
+      where TViewModel : class;
+
+    /// <summary>Creates a view model without a matching view</summary>
+    /// <typeparam name="TViewModel">Type of view model that will be created</typeparam>
+    /// <returns>The new view model</returns>
+    /// <remarks>
+    ///   <para>
+    ///     This is useful if a view model needs to create child view models (i.e. paged container
+    ///     and wants to ensure the same dependency injector (if any) if used as the window
+    ///     manager uses for other view models it creates.
+    ///   </para>
+    ///   <para>
+    ///     This way, view models can set up their child view models without having to immediately
+    ///     bind a view to them. Later on, views can use the window manager to create a matching
+    ///     child view and store it in a container.
+    ///   </para>
+    /// </remarks>
+    TViewModel CreateViewModel<TViewModel>()
+      where TViewModel : class;
+
+  }
+
+} // namespace Nuclex.Avalonia
+
diff --git a/Source/Messages/AvaloniaMessagePresenter.cs b/Source/Messages/AvaloniaMessagePresenter.cs
index e7c181b..af5345b 100644
--- a/Source/Messages/AvaloniaMessagePresenter.cs
+++ b/Source/Messages/AvaloniaMessagePresenter.cs
@@ -1,188 +1,188 @@
-#region Apache License 2.0
-/*
-Nuclex Foundation libraries for .NET
-Copyright (C) 2002-2025 Markus Ewald / Nuclex Development Labs
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-#endregion // Apache License 2.0
-
-using System;
-using System.Threading.Tasks;
-using System.Diagnostics;
-using System.Runtime.InteropServices;
-using System.Runtime.Versioning;
-#if NET6_0_OR_GREATER
-using System.Runtime.Versioning;
-#endif
-
-using Avalonia.Controls;
-
-using MessageBoxIcon = MsBox.Avalonia.Enums.Icon;
-using MessageBoxButtons = MsBox.Avalonia.Enums.ButtonEnum;
-using MessageDialogResult = MsBox.Avalonia.Enums.ButtonResult;
-
-namespace Nuclex.Avalonia.Messages {
-
-  /// <summary>Uses Avalonia to display message boxes</summary>
-  public class AvaloniaMessagePresenter : IMessageService {
-
-    #region class MessageScope
-
-    /// <summary>Triggers the message displayed and acknowledged events</summary>
-    private class MessageScope : IDisposable {
-
-      /// <summary>
-      ///   Initializes a new message scope, triggering the message displayed event
-      /// </summary>
-      /// <param name="self">Message service the scope belongs to</param>
-      /// <param name="image">Image of the message being displayed</param>
-      /// <param name="text">Text contained in the message being displayed</param>
-      public MessageScope(
-        AvaloniaMessagePresenter self, MessageBoxIcon image, MessageText text
-      ) {
-        EventHandler<MessageEventArgs>? messageDisplayed = self.MessageDisplaying;
-        if(messageDisplayed != null) {
-          messageDisplayed(this, new MessageEventArgs(image, text));
-        }
-
-        this.self = self;
-      }
-
-      /// <summary>Triggers the message acknowledged event</summary>
-      public void Dispose() {
-        EventHandler? messageAcknowledged = self.MessageAcknowledged;
-        if(messageAcknowledged != null) {
-          messageAcknowledged(this, EventArgs.Empty);
-        }
-      }
-
-      /// <summary>Message service the scope belongs to</summary>
-      private AvaloniaMessagePresenter self;
-
-    }
-
-    #endregion // class MessageScope
-
-    /// <summary>Triggered when a message is displayed to the user</summary>
-    public event EventHandler<MessageEventArgs>? MessageDisplaying;
-
-    /// <summary>Triggered when the user has acknowledged the current message</summary>
-    public event EventHandler? MessageAcknowledged;
-
-    /// <summary>Initializes a new Avalonia message service</summary>
-    /// <param name="tracker">Used to determine the current top-level window</param>
-    public AvaloniaMessagePresenter(IActiveWindowTracker tracker) {
-      this.tracker = tracker;
-    }
-
-    /// <summary>Asks the user a question that can be answered via several buttons</summary>
-    /// <param name="image">Image that will be shown on the message box</param>
-    /// <param name="text">Text that will be shown to the user</param>
-    /// <param name="buttons">Buttons available for the user to click on</param>
-    /// <returns>The button the user has clicked on</returns>
-    public Task<MessageDialogResult> ShowQuestionAsync(
-      MessageBoxIcon image, MessageText text, MessageBoxButtons buttons
-    ) {
-      using(var scope = new MessageScope(this, image, text)) {
-        MsBox.Avalonia.Base.IMsBox<MessageDialogResult> messageBox = (
-          MsBox.Avalonia.MessageBoxManager.GetMessageBoxStandard(
-            new MsBox.Avalonia.Dto.MessageBoxStandardParams() {
-              ContentTitle = text.Caption,
-              ContentHeader = text.Message,
-              ContentMessage = text.Details ?? string.Empty,
-              ButtonDefinitions = buttons,
-              Icon = image,
-              WindowStartupLocation = WindowStartupLocation.CenterOwner
-            }
-          )
-        );
-        return messageBox.ShowAsync(); // TODO: Make modal to current or main window
-      }
-    }
-
-    /// <summary>Displays a notification to the user</summary>
-    /// <param name="image">Image that will be shown on the message bx</param>
-    /// <param name="text">Text that will be shown to the user</param>
-    public Task ShowNotificationAsync(MessageBoxIcon image, MessageText text) {
-      using(var scope = new MessageScope(this, image, text)) {
-        MsBox.Avalonia.Base.IMsBox<MessageDialogResult> messageBox = (
-          MsBox.Avalonia.MessageBoxManager.GetMessageBoxStandard(
-            new MsBox.Avalonia.Dto.MessageBoxStandardParams() {
-              ContentTitle = text.Caption,
-              ContentHeader = text.Message,
-              ContentMessage = text.Details ?? string.Empty,
-              ButtonDefinitions = MessageBoxButtons.Ok,
-              Icon = image,
-              WindowStartupLocation = WindowStartupLocation.CenterOwner
-            }
-          )
-        );
-
-        Window? activeWindow = this.tracker.ActiveWindow;
-        if(activeWindow == null) {
-          return messageBox.ShowAsync();
-        } else {
-          //return messageBox.ShowAsPopupAsync(activeWindow);
-          return messageBox.ShowWindowDialogAsync(activeWindow);
-        }
-      }
-    }
-
-    /// <summary>Reports an error using the system's message box functions</summary>
-    /// <param name="title">Title of the message box</param>
-    /// <param name="message">Message text that will be displayed</param>
-    public static void FallbackReportError(string title, string message) {
-      // TODO: Escape quotes for the command-line tools
-      // TODO: Wait for the child process to exit so display is certain
-
-      if(RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) {
-        MessageBoxW(IntPtr.Zero, message, title, MB_OK | MB_ICONEXCLAMATION);
-      } else if(RuntimeInformation.IsOSPlatform(OSPlatform.Linux)) {
-        Process.Start("zenity", $"--error --title=\"{title}\" --text=\"{message}\"");
-      } else if(RuntimeInformation.IsOSPlatform(OSPlatform.OSX)) {
-        Process.Start("osascript", $"-e 'display dialog \"{message}\" with title \"{title}\" with icon stop'");
-      }
-    }
-
-    /// <summary>Windows only: display a message box with an OK button</summary>
-#if NET6_0_OR_GREATER
-  [SupportedOSPlatform("windows")]
-#endif
-    private const uint MB_OK = 0x00000000;
-
-    /// <summary>Windows only: display a message box with an Exclamation icon</summary>
-#if NET6_0_OR_GREATER
-  [SupportedOSPlatform("windows")]
-#endif
-    private const uint MB_ICONEXCLAMATION = 0x00000030;
-
-    /// <summary>Windows only: displays a native Windows message box</summary>
-    /// <param name="parentWindowHandle">Handle of the window that owns the message box</param>
-    /// <param name="text">Text that should be in the message box</param>
-    /// <param name="caption">Caption or window title of the message box</param>
-    /// <param name="type">Which icons and buttons that message box should have</param>
-    /// <returns>How the user closed the message box and which button they clicked</returns>
-    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
-#if NET6_0_OR_GREATER
-  [SupportedOSPlatform("windows")]
-#endif
-    private static extern int MessageBoxW(IntPtr parentWindowHandle, string text, string caption, uint type);
-
-    // <summary>Provides the currently active top-level window</summary>
-    private IActiveWindowTracker tracker;
-
-  }
-
-} // namespace Nuclex.Avalonia.Messages
-
+#region Apache License 2.0
+/*
+Nuclex Foundation libraries for .NET
+Copyright (C) 2002-2025 Markus Ewald / Nuclex Development Labs
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+#endregion // Apache License 2.0
+
+using System;
+using System.Threading.Tasks;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
+#if NET6_0_OR_GREATER
+using System.Runtime.Versioning;
+#endif
+
+using Avalonia.Controls;
+
+using MessageBoxIcon = MsBox.Avalonia.Enums.Icon;
+using MessageBoxButtons = MsBox.Avalonia.Enums.ButtonEnum;
+using MessageDialogResult = MsBox.Avalonia.Enums.ButtonResult;
+
+namespace Nuclex.Avalonia.Messages {
+
+  /// <summary>Uses Avalonia to display message boxes</summary>
+  public class AvaloniaMessagePresenter : IMessageService {
+
+    #region class MessageScope
+
+    /// <summary>Triggers the message displayed and acknowledged events</summary>
+    private class MessageScope : IDisposable {
+
+      /// <summary>
+      ///   Initializes a new message scope, triggering the message displayed event
+      /// </summary>
+      /// <param name="self">Message service the scope belongs to</param>
+      /// <param name="image">Image of the message being displayed</param>
+      /// <param name="text">Text contained in the message being displayed</param>
+      public MessageScope(
+        AvaloniaMessagePresenter self, MessageBoxIcon image, MessageText text
+      ) {
+        EventHandler<MessageEventArgs>? messageDisplayed = self.MessageDisplaying;
+        if(messageDisplayed != null) {
+          messageDisplayed(this, new MessageEventArgs(image, text));
+        }
+
+        this.self = self;
+      }
+
+      /// <summary>Triggers the message acknowledged event</summary>
+      public void Dispose() {
+        EventHandler? messageAcknowledged = self.MessageAcknowledged;
+        if(messageAcknowledged != null) {
+          messageAcknowledged(this, EventArgs.Empty);
+        }
+      }
+
+      /// <summary>Message service the scope belongs to</summary>
+      private AvaloniaMessagePresenter self;
+
+    }
+
+    #endregion // class MessageScope
+
+    /// <summary>Triggered when a message is displayed to the user</summary>
+    public event EventHandler<MessageEventArgs>? MessageDisplaying;
+
+    /// <summary>Triggered when the user has acknowledged the current message</summary>
+    public event EventHandler? MessageAcknowledged;
+
+    /// <summary>Initializes a new Avalonia message service</summary>
+    /// <param name="tracker">Used to determine the current top-level window</param>
+    public AvaloniaMessagePresenter(IActiveWindowTracker tracker) {
+      this.tracker = tracker;
+    }
+
+    /// <summary>Asks the user a question that can be answered via several buttons</summary>
+    /// <param name="image">Image that will be shown on the message box</param>
+    /// <param name="text">Text that will be shown to the user</param>
+    /// <param name="buttons">Buttons available for the user to click on</param>
+    /// <returns>The button the user has clicked on</returns>
+    public Task<MessageDialogResult> ShowQuestionAsync(
+      MessageBoxIcon image, MessageText text, MessageBoxButtons buttons
+    ) {
+      using(var scope = new MessageScope(this, image, text)) {
+        MsBox.Avalonia.Base.IMsBox<MessageDialogResult> messageBox = (
+          MsBox.Avalonia.MessageBoxManager.GetMessageBoxStandard(
+            new MsBox.Avalonia.Dto.MessageBoxStandardParams() {
+              ContentTitle = text.Caption,
+              ContentHeader = text.Message,
+              ContentMessage = text.Details ?? string.Empty,
+              ButtonDefinitions = buttons,
+              Icon = image,
+              WindowStartupLocation = WindowStartupLocation.CenterOwner
+            }
+          )
+        );
+        return messageBox.ShowAsync(); // TODO: Make modal to current or main window
+      }
+    }
+
+    /// <summary>Displays a notification to the user</summary>
+    /// <param name="image">Image that will be shown on the message bx</param>
+    /// <param name="text">Text that will be shown to the user</param>
+    public Task ShowNotificationAsync(MessageBoxIcon image, MessageText text) {
+      using(var scope = new MessageScope(this, image, text)) {
+        MsBox.Avalonia.Base.IMsBox<MessageDialogResult> messageBox = (
+          MsBox.Avalonia.MessageBoxManager.GetMessageBoxStandard(
+            new MsBox.Avalonia.Dto.MessageBoxStandardParams() {
+              ContentTitle = text.Caption,
+              ContentHeader = text.Message,
+              ContentMessage = text.Details ?? string.Empty,
+              ButtonDefinitions = MessageBoxButtons.Ok,
+              Icon = image,
+              WindowStartupLocation = WindowStartupLocation.CenterOwner
+            }
+          )
+        );
+
+        Window? activeWindow = this.tracker.ActiveWindow;
+        if(activeWindow == null) {
+          return messageBox.ShowAsync();
+        } else {
+          //return messageBox.ShowAsPopupAsync(activeWindow);
+          return messageBox.ShowWindowDialogAsync(activeWindow);
+        }
+      }
+    }
+
+    /// <summary>Reports an error using the system's message box functions</summary>
+    /// <param name="title">Title of the message box</param>
+    /// <param name="message">Message text that will be displayed</param>
+    public static void FallbackReportError(string title, string message) {
+      // TODO: Escape quotes for the command-line tools
+      // TODO: Wait for the child process to exit so display is certain
+
+      if(RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) {
+        MessageBoxW(IntPtr.Zero, message, title, MB_OK | MB_ICONEXCLAMATION);
+      } else if(RuntimeInformation.IsOSPlatform(OSPlatform.Linux)) {
+        Process.Start("zenity", $"--error --title=\"{title}\" --text=\"{message}\"");
+      } else if(RuntimeInformation.IsOSPlatform(OSPlatform.OSX)) {
+        Process.Start("osascript", $"-e 'display dialog \"{message}\" with title \"{title}\" with icon stop'");
+      }
+    }
+
+    /// <summary>Windows only: display a message box with an OK button</summary>
+#if NET6_0_OR_GREATER
+  [SupportedOSPlatform("windows")]
+#endif
+    private const uint MB_OK = 0x00000000;
+
+    /// <summary>Windows only: display a message box with an Exclamation icon</summary>
+#if NET6_0_OR_GREATER
+  [SupportedOSPlatform("windows")]
+#endif
+    private const uint MB_ICONEXCLAMATION = 0x00000030;
+
+    /// <summary>Windows only: displays a native Windows message box</summary>
+    /// <param name="parentWindowHandle">Handle of the window that owns the message box</param>
+    /// <param name="text">Text that should be in the message box</param>
+    /// <param name="caption">Caption or window title of the message box</param>
+    /// <param name="type">Which icons and buttons that message box should have</param>
+    /// <returns>How the user closed the message box and which button they clicked</returns>
+    [DllImport("user32.dll", CharSet = CharSet.Unicode)]
+#if NET6_0_OR_GREATER
+  [SupportedOSPlatform("windows")]
+#endif
+    private static extern int MessageBoxW(IntPtr parentWindowHandle, string text, string caption, uint type);
+
+    // <summary>Provides the currently active top-level window</summary>
+    private IActiveWindowTracker tracker;
+
+  }
+
+} // namespace Nuclex.Avalonia.Messages
+