diff --git a/src/AddIns/Misc/AddInManager2/Project/AddInManager2.csproj b/src/AddIns/Misc/AddInManager2/Project/AddInManager2.csproj
index 90eeb233d2..bdcbd9ba89 100644
--- a/src/AddIns/Misc/AddInManager2/Project/AddInManager2.csproj
+++ b/src/AddIns/Misc/AddInManager2/Project/AddInManager2.csproj
@@ -77,6 +77,7 @@
     <Resource Include="Resources\sd_packageicon.png" />
     <Resource Include="Resources\accept.png" />
     <Resource Include="Resources\exclamation.png" />
+    <Resource Include="Resources\external_addin_small.png" />
     <None Include="Resources\license.txt" />
     <Resource Include="Resources\magnifier.png" />
     <Resource Include="Resources\packageicon.png" />
@@ -110,7 +111,7 @@
     <Compile Include="Src\Model\NuGetPackageManager.cs" />
     <Compile Include="Src\Model\AddInSetup.cs" />
     <Compile Include="Src\Model\AddInManagerEvents.cs" />
-    <Compile Include="Src\Model\AddInExceptionEventArgs.cs" />
+    <Compile Include="Src\Model\AddInOperationErrorEventArgs.cs" />
     <Compile Include="Src\Model\NuGetPackageOperationEventArgs.cs" />
     <Compile Include="Src\Model\PackageMessageLoggedEventArgs.cs" />
     <Compile Include="Src\Model\PackageRepositories.cs" />
diff --git a/src/AddIns/Misc/AddInManager2/Project/Resources/StringResources.resx b/src/AddIns/Misc/AddInManager2/Project/Resources/StringResources.resx
index fa78b641fc..b0d2f7ecb2 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Resources/StringResources.resx
+++ b/src/AddIns/Misc/AddInManager2/Project/Resources/StringResources.resx
@@ -236,7 +236,7 @@ If you do not agree to the license terms click "I Decline".</value>
     <value>License Agreements</value>
   </data>
   <data name="AddInManager2.SDAddInFileFilter" xml:space="preserve">
-    <value>SharpDevelop AddIns|*.sdaddin|All files|*.*</value>
+    <value>SharpDevelop AddIns|*.sdaddin;*.addin|All files|*.*</value>
   </data>
   <data name="AddInManager2.InstallDependentMessage" xml:space="preserve">
     <value>Package "{0}" needs at least one additional package:
@@ -254,4 +254,7 @@ The application will try to download and install them, as well. Do you want to c
   <data name="AddInManager2.Details.FileName" xml:space="preserve">
     <value>File name:</value>
   </data>
+  <data name="AddInManager2.InvalidPackage" xml:space="preserve">
+    <value>Selected package doesn't contain a valid SharpDevelop AddIn.</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/src/AddIns/Misc/AddInManager2/Project/Resources/external_addin_small.png b/src/AddIns/Misc/AddInManager2/Project/Resources/external_addin_small.png
new file mode 100644
index 0000000000..ac945975af
Binary files /dev/null and b/src/AddIns/Misc/AddInManager2/Project/Resources/external_addin_small.png differ
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInExceptionEventArgs.cs b/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInExceptionEventArgs.cs
deleted file mode 100644
index 9cc0a54d2b..0000000000
--- a/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInExceptionEventArgs.cs
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
-// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
-
-using System;
-
-namespace ICSharpCode.AddInManager2.Model
-{
-	/// <summary>
-	/// Data for events indicating an exception during package-related operations.
-	/// </summary>
-	public class AddInExceptionEventArgs : EventArgs
-	{
-		public AddInExceptionEventArgs(Exception exception)
-		{
-			Exception = exception;
-		}
-		
-		public Exception Exception
-		{
-			get;
-			private set;
-		}
-	}
-}
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInManagerEvents.cs b/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInManagerEvents.cs
index 7bf7cddff2..c77bf3bab3 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInManagerEvents.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInManagerEvents.cs
@@ -13,6 +13,14 @@ namespace ICSharpCode.AddInManager2.Model
 	{
 		public event EventHandler OperationStarted;
 		
+		public void OnOperationStarted()
+		{
+			if (OperationStarted != null)
+			{
+				OperationStarted(this, new EventArgs());
+			}
+		}
+		
 		public void OnOperationStarted(EventArgs e)
 		{
 			if (OperationStarted != null)
@@ -41,9 +49,9 @@ namespace ICSharpCode.AddInManager2.Model
 			}
 		}
 		
-		public event EventHandler<AddInExceptionEventArgs> AddInOperationError;
+		public event EventHandler<AddInOperationErrorEventArgs> AddInOperationError;
 		
-		public void OnAddInOperationError(AddInExceptionEventArgs e)
+		public void OnAddInOperationError(AddInOperationErrorEventArgs e)
 		{
 			if (AddInOperationError != null)
 			{
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInOperationErrorEventArgs.cs b/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInOperationErrorEventArgs.cs
new file mode 100644
index 0000000000..a65310f4b7
--- /dev/null
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInOperationErrorEventArgs.cs
@@ -0,0 +1,49 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+
+namespace ICSharpCode.AddInManager2.Model
+{
+	/// <summary>
+	/// Data for events indicating an exception or other errors during package-related operations.
+	/// </summary>
+	public class AddInOperationErrorEventArgs : EventArgs
+	{
+		private string _message = null;
+		
+		public AddInOperationErrorEventArgs(Exception exception)
+		{
+			Exception = exception;
+		}
+		
+		public AddInOperationErrorEventArgs(string message)
+		{
+			Exception = null;
+			_message = message;
+		}
+		
+		public Exception Exception
+		{
+			get;
+			private set;
+		}
+		
+		public string Message
+		{
+			get
+			{
+				if (_message != null)
+				{
+					return _message;
+				}
+				if (Exception != null)
+				{
+					return Exception.Message;
+				}
+				
+				return null;
+			}
+		}
+	}
+}
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInSetup.cs b/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInSetup.cs
index af7b03b298..6476c0b050 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInSetup.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/Model/AddInSetup.cs
@@ -56,7 +56,7 @@ namespace ICSharpCode.AddInManager2.Model
 			}
 			catch (Exception ex)
 			{
-				_events.OnAddInOperationError(new AddInExceptionEventArgs(ex));
+				_events.OnAddInOperationError(new AddInOperationErrorEventArgs(ex));
 			}
 		}
 		
@@ -71,8 +71,9 @@ namespace ICSharpCode.AddInManager2.Model
 					if (addInEntry != null)
 					{
 						_events.OnAddInOperationError(
-							new AddInExceptionEventArgs(
-								new AddInLoadException("The package may only contain one .addin file.")));
+							new AddInOperationErrorEventArgs(
+								SD.ResourceService.GetString("AddInManager2.InvalidPackage")));
+						return null;
 					}
 					addInEntry = entry;
 				}
@@ -80,8 +81,9 @@ namespace ICSharpCode.AddInManager2.Model
 			if (addInEntry == null)
 			{
 				_events.OnAddInOperationError(
-					new AddInExceptionEventArgs(
-						new AddInLoadException("The package must contain one .addin file.")));
+					new AddInOperationErrorEventArgs(
+						SD.ResourceService.GetString("AddInManager2.InvalidPackage")));
+				return null;
 			}
 			using (Stream s = file.GetInputStream(addInEntry))
 			{
@@ -100,22 +102,28 @@ namespace ICSharpCode.AddInManager2.Model
 			{
 				AddIn addIn = null;
 				
+				bool installAsExternal = false;
+				
 				switch (Path.GetExtension(fileName).ToLowerInvariant())
 				{
 					case ".addin":
 						if (FileUtility.IsBaseDirectory(FileUtility.ApplicationRootPath, fileName))
 						{
-							// TODO Send around the error message
-//							MessageService.ShowMessage("${res:AddInManager.CannotInstallIntoApplicationDirectory}");
+							// Don't allow to install AddIns from application root path
+							_events.OnAddInOperationError(
+								new AddInOperationErrorEventArgs(
+									SD.ResourceService.GetString("AddInManager.CannotInstallIntoApplicationDirectory")));
 							return null;
 						}
 						
 						// Load directly from location
 						addIn = _sdAddInManagement.Load(fileName);
+						installAsExternal = true;
 						
 						break;
 						
 					case ".sdaddin":
+					case ".zip":
 						// Try to load the *.sdaddin file as ZIP archive
 						ZipFile zipFile = null;
 						try
@@ -123,10 +131,12 @@ namespace ICSharpCode.AddInManager2.Model
 							zipFile = new ZipFile(fileName);
 							addIn = LoadAddInFromZip(zipFile);
 						}
-						catch (Exception ex)
+						catch (Exception)
 						{
-							// Report the exception
-							_events.OnAddInOperationError(new AddInExceptionEventArgs(ex));
+							// ZIP file seems not to be valid
+							_events.OnAddInOperationError(
+								new AddInOperationErrorEventArgs(
+									SD.ResourceService.GetString("AddInManager2.InvalidPackage")));
 							return null;
 						}
 						finally
@@ -139,8 +149,10 @@ namespace ICSharpCode.AddInManager2.Model
 						break;
 						
 					default:
-						// TODO Send around the error message
-//							MessageService.ShowMessage("${res:AddInManager.UnknownFileFormat} " + Path.GetExtension(file));
+						// Unknown format of file
+						_events.OnAddInOperationError(
+							new AddInOperationErrorEventArgs(
+								SD.ResourceService.GetString("AddInManager.UnknownFileFormat") + " " + Path.GetExtension(fileName)));
 						return null;
 				}
 				
@@ -149,7 +161,7 @@ namespace ICSharpCode.AddInManager2.Model
 					if ((addIn.Manifest == null) || (addIn.Manifest.PrimaryIdentity == null))
 					{
 						_events.OnAddInOperationError(
-							new AddInExceptionEventArgs(
+							new AddInOperationErrorEventArgs(
 								new AddInLoadException(SD.ResourceService.GetString("AddInManager.AddInMustHaveIdentity"))));
 						return null;
 					}
@@ -172,18 +184,26 @@ namespace ICSharpCode.AddInManager2.Model
 						_sdAddInManagement.AbortRemoveUserAddInOnNextStart(installedIdentity);
 					}
 					
-					// Create target directory for AddIn in user profile & copy package contents there
-					CopyAddInFromZip(addIn, fileName);
-					
-					// Install the AddIn using manifest
-					if (foundAddIn != null)
+					if (!installAsExternal)
 					{
-						addIn.Action = AddInAction.Update;
+						// Create target directory for AddIn in user profile & copy package contents there
+						CopyAddInFromZip(addIn, fileName);
+						
+						// Install the AddIn using manifest
+						if (foundAddIn != null)
+						{
+							addIn.Action = AddInAction.Update;
+						}
+						else
+						{
+							addIn.Action = AddInAction.Install;
+							_sdAddInManagement.AddToTree(addIn);
+						}
 					}
 					else
 					{
-						addIn.Action = AddInAction.Install;
-						_sdAddInManagement.AddToTree(addIn);
+						// Only add a reference to an external manifest
+						_sdAddInManagement.AddExternalAddIns(new AddIn[] { addIn });
 					}
 					
 					// Mark this AddIn
@@ -202,13 +222,9 @@ namespace ICSharpCode.AddInManager2.Model
 					
 					return addIn;
 				}
-				else
-				{
-					// This is not a valid SharpDevelop AddIn package!
-					// TODO Show a message to user!
-				}
 			}
 
+			// In successful cases we should have exited somewhere else, in error cases the error event was already fired.
 			return null;
 		}
 		
@@ -222,7 +238,7 @@ namespace ICSharpCode.AddInManager2.Model
 				if (addIn.Manifest.PrimaryIdentity == null)
 				{
 					_events.OnAddInOperationError(
-						new AddInExceptionEventArgs(
+						new AddInOperationErrorEventArgs(
 							new AddInLoadException(SD.ResourceService.GetString("AddInManager.AddInMustHaveIdentity"))));
 					return null;
 				}
@@ -278,7 +294,9 @@ namespace ICSharpCode.AddInManager2.Model
 			else
 			{
 				// This is not a valid SharpDevelop AddIn package!
-				// TODO Throw something.
+				_events.OnAddInOperationError(
+					new AddInOperationErrorEventArgs(
+						SD.ResourceService.GetString("AddInManager2.InvalidPackage")));
 			}
 
 			return null;
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/IAddInManagerEvents.cs b/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/IAddInManagerEvents.cs
index 30a7de7441..d774903567 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/IAddInManagerEvents.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/IAddInManagerEvents.cs
@@ -13,6 +13,7 @@ namespace ICSharpCode.AddInManager2.Model
 	{
 		event EventHandler OperationStarted;
 		void OnOperationStarted(EventArgs e);
+		void OnOperationStarted();
 		
 		event EventHandler<AddInInstallationEventArgs> AddInInstalled;
 		void OnAddInInstalled(AddInInstallationEventArgs e);
@@ -20,8 +21,8 @@ namespace ICSharpCode.AddInManager2.Model
 		event EventHandler<AddInInstallationEventArgs> AddInUninstalled;
 		void OnAddInUninstalled(AddInInstallationEventArgs e);
 		
-		event EventHandler<AddInExceptionEventArgs> AddInOperationError;
-		void OnAddInOperationError(AddInExceptionEventArgs e);
+		event EventHandler<AddInOperationErrorEventArgs> AddInOperationError;
+		void OnAddInOperationError(AddInOperationErrorEventArgs e);
 		
 		event EventHandler<PackageOperationEventArgs> AddInPackageDownloaded;
 		void OnAddInPackageDownloaded(PackageOperationEventArgs e);
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/ISDAddInManagement.cs b/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/ISDAddInManagement.cs
index ea814a7371..a56af15da4 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/ISDAddInManagement.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/ISDAddInManagement.cs
@@ -35,5 +35,6 @@ namespace ICSharpCode.AddInManager2.Model
 		void RemoveUserAddInOnNextStart(string identity);
 		AddIn Load(TextReader textReader);
 		AddIn Load(string fileName);
+		void AddExternalAddIns(IList<AddIn> addIns);
 	}
 }
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/Model/SDAddInManagement.cs b/src/AddIns/Misc/AddInManager2/Project/Src/Model/SDAddInManagement.cs
index 0bde903869..d716c79c39 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/Model/SDAddInManagement.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/Model/SDAddInManagement.cs
@@ -84,5 +84,10 @@ namespace ICSharpCode.AddInManager2.Model
 		{
 			return AddIn.Load(SD.AddInTree, fileName);
 		}
+		
+		public void AddExternalAddIns(IList<AddIn> addIns)
+		{
+			ICSharpCode.Core.AddInManager.AddExternalAddIns(addIns);
+		}
 	}
 }
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInManagerView.xaml b/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInManagerView.xaml
index db56187271..45f416a5bb 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInManagerView.xaml
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInManagerView.xaml
@@ -20,6 +20,25 @@
 		<BitmapImage x:Key="ErrorIcon"
 		             UriSource="pack://application:,,,/ICSharpCode.AddInManager2;component/Resources/exclamation.png"/>
 		
+		<Style x:Key="errorImageStyle" TargetType="{x:Type Image}">
+			<Setter Property="Visibility" Value="{Binding Path=HasError, Converter={StaticResource BoolToVisibility}}" />
+			<Setter Property="Source" Value="{StaticResource ErrorIcon}" />
+			<Style.Triggers>
+				<DataTrigger Binding="{Binding Path=HasError}" Value="True">
+					<DataTrigger.EnterActions>
+						<BeginStoryboard Name="BlinkingIconStoryboard">
+							<Storyboard>
+								<DoubleAnimation
+									RepeatBehavior="Forever" AutoReverse="True"
+									From="1" To="0" Duration="0:0:0.75"
+									Storyboard.TargetProperty="Opacity" />
+							</Storyboard>
+						</BeginStoryboard>
+					</DataTrigger.EnterActions>
+				</DataTrigger>
+			</Style.Triggers>
+		</Style>
+		
 		<Style x:Key="tabHeaderTextStyle" TargetType="{x:Type TextBlock}">
 			<Style.Triggers>
 				<DataTrigger Binding="{Binding DataContext.HasHighlightCount}" Value="True">
@@ -60,8 +79,7 @@
 			<StackPanel>
 				<Image
 					Margin="4, 4"
-					Visibility="{Binding Path=HasError, Converter={StaticResource BoolToVisibility}}"
-					Source="{StaticResource ErrorIcon}"/>
+					Style="{StaticResource errorImageStyle}" />
 			</StackPanel>
 			<TextBlock
 				Grid.Column="1"
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInsView.xaml b/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInsView.xaml
index 93c137a4e9..93ca4e852f 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInsView.xaml
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/View/AddInsView.xaml
@@ -19,6 +19,8 @@
 		             UriSource="pack://application:,,,/ICSharpCode.AddInManager2;component/Resources/packageicon_small.png"/>
 		<BitmapImage x:Key="SDPackageIcon"
 		             UriSource="pack://application:,,,/ICSharpCode.AddInManager2;component/Resources/sd_packageicon.png"/>
+		<BitmapImage x:Key="SmallExternalAddInIcon"
+		             UriSource="pack://application:,,,/ICSharpCode.AddInManager2;component/Resources/external_addin_small.png"/>
 		<BitmapImage x:Key="PackageAddedIcon"
 		             UriSource="pack://application:,,,/ICSharpCode.AddInManager2;component/Resources/accept.png"/>
 		<BitmapImage x:Key="SearchIcon"
@@ -53,6 +55,16 @@
 			</Style.Triggers>
 		</Style>
 		
+		<Style x:Key="AddInExternalStateImageStyle" TargetType="{x:Type Image}">
+			<Setter Property="Source" Value="{StaticResource SmallExternalAddInIcon}" />
+			<Setter Property="Visibility" Value="{Binding Path=IsExternallyReferenced, Converter={StaticResource BoolToVisibility}}" />
+			<Style.Triggers>
+				<DataTrigger Binding="{Binding IsEnabled}" Value="False">
+					<Setter Property="Opacity" Value="0.5" />
+				</DataTrigger>
+			</Style.Triggers>
+		</Style>
+		
 		<Style x:Key="addInListButtonStyle" TargetType="{x:Type Button}" BasedOn="{x:Static core:GlobalStyles.ButtonStyle}">
 			<Setter Property="Visibility" Value="Collapsed" />
 			<Style.Triggers>
@@ -97,6 +109,12 @@
 					Margin="36,0,0,0"
 					VerticalAlignment="Top"
 					Style="{StaticResource AddInOnlineStateImageStyle}" />
+				<Image
+					Grid.Column="0"
+					Height="16"
+					Margin="36,0,0,0"
+					VerticalAlignment="Top"
+					Style="{StaticResource AddInExternalStateImageStyle}" />
 				<StackPanel
 					Grid.Column="1"
 					Margin="4, 0">
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInManagerViewModel.cs b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInManagerViewModel.cs
index 9c9157ec15..2bf915dc19 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInManagerViewModel.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInManagerViewModel.cs
@@ -39,7 +39,7 @@ namespace ICSharpCode.AddInManager2.ViewModel
 			
 			// Add event handlers
 			AddInManager.Events.OperationStarted += AddInManager_Events_OperationStarted;
-			AddInManager.Events.AddInOperationError += AddInManager_Events_NuGetPackageOperationError;
+			AddInManager.Events.AddInOperationError += AddInManager_Events_AddInOperationError;
 			AddInManager.Events.AcceptLicenses += AddInManager_Events_AcceptLicenses;
 			
 			AvailableAddInsViewModel = new AvailableAddInsViewModel();
@@ -79,7 +79,8 @@ namespace ICSharpCode.AddInManager2.ViewModel
 		
 		public void Dispose()
 		{
-			AddInManager.Events.AddInOperationError -= AddInManager_Events_NuGetPackageOperationError;
+			AddInManager.Events.OperationStarted -= AddInManager_Events_OperationStarted;
+			AddInManager.Events.AddInOperationError -= AddInManager_Events_AddInOperationError;
 			AddInManager.Events.AcceptLicenses -= AddInManager_Events_AcceptLicenses;
 		}
 		
@@ -126,9 +127,9 @@ namespace ICSharpCode.AddInManager2.ViewModel
 			this.HasError = false;
 		}
 		
-		private void AddInManager_Events_NuGetPackageOperationError(object sender, AddInExceptionEventArgs e)
+		private void AddInManager_Events_AddInOperationError(object sender, AddInOperationErrorEventArgs e)
 		{
-			ShowErrorMessage(e.Exception.Message);
+			ShowErrorMessage(e.Message);
 		}
 		
 		private void AddInManager_Events_AcceptLicenses(object sender, AcceptLicensesEventArgs e)
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInPackageViewModelBase.cs b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInPackageViewModelBase.cs
index d6ca66d934..1d5f863cdb 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInPackageViewModelBase.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/AddInPackageViewModelBase.cs
@@ -220,6 +220,14 @@ namespace ICSharpCode.AddInManager2.ViewModel
 			get;
 		}
 		
+		public virtual bool IsExternallyReferenced
+		{
+			get
+			{
+				return false;
+			}
+		}
+		
 		public abstract bool IsPreinstalled
 		{
 			get;
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/InstalledAddInsViewModel.cs b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/InstalledAddInsViewModel.cs
index 5c1697dcfc..282b67ff61 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/InstalledAddInsViewModel.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/InstalledAddInsViewModel.cs
@@ -125,7 +125,7 @@ namespace ICSharpCode.AddInManager2.ViewModel
 					}
 				}
 				
-				addInPackage = new OfflineAddInsViewModelBase(addIn);
+				addInPackage = new OfflineAddInsViewModel(addIn);
 				yield return addInPackage;
 			}
 		}
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/NuGetPackageViewModel.cs b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/NuGetPackageViewModel.cs
index aad83f6db0..35d2272aa8 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/NuGetPackageViewModel.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/NuGetPackageViewModel.cs
@@ -307,7 +307,8 @@ namespace ICSharpCode.AddInManager2.ViewModel
 
 		private void ClearReportedMessages()
 		{
-			//			packageManagementEvents.OnPackageOperationsStarting();
+			// Notify about new operation
+			AddInManager.Events.OnOperationStarted();
 		}
 
 		private void GetPackageOperations()
@@ -417,11 +418,12 @@ namespace ICSharpCode.AddInManager2.ViewModel
 
 		private void ReportError(Exception ex)
 		{
-			AddInManager.Events.OnAddInOperationError(new AddInExceptionEventArgs(ex));
+			AddInManager.Events.OnAddInOperationError(new AddInOperationErrorEventArgs(ex));
 		}
 
 		public override void RemovePackage()
 		{
+			ClearReportedMessages();
 			TryUninstallingPackage();
 		}
 
@@ -451,6 +453,8 @@ namespace ICSharpCode.AddInManager2.ViewModel
 		
 		public override void CancelInstallation()
 		{
+			ClearReportedMessages();
+			
 			AddIn addIn = AddInManager.Setup.GetAddInForNuGetPackage(_package, true);
 			if (addIn != null)
 			{
@@ -460,6 +464,8 @@ namespace ICSharpCode.AddInManager2.ViewModel
 		
 		public override void CancelUpdate()
 		{
+			ClearReportedMessages();
+			
 			AddIn addIn = AddInManager.Setup.GetAddInForNuGetPackage(_package, true);
 			if (addIn != null)
 			{
@@ -469,6 +475,8 @@ namespace ICSharpCode.AddInManager2.ViewModel
 		
 		public override void CancelUninstallation()
 		{
+			ClearReportedMessages();
+			
 			AddIn addIn = AddInManager.Setup.GetAddInForNuGetPackage(_package);
 			if (addIn != null)
 			{
diff --git a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/OfflineAddInViewModel.cs b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/OfflineAddInViewModel.cs
index 3eee3f69d4..64edb36d50 100644
--- a/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/OfflineAddInViewModel.cs
+++ b/src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/OfflineAddInViewModel.cs
@@ -12,7 +12,7 @@ using NuGet;
 
 namespace ICSharpCode.AddInManager2.ViewModel
 {
-	public class OfflineAddInsViewModelBase : AddInPackageViewModelBase
+	public class OfflineAddInsViewModel : AddInPackageViewModelBase
 	{
 		private AddIn _addIn;
 		private ManagedAddIn _markedAddIn;
@@ -33,13 +33,13 @@ namespace ICSharpCode.AddInManager2.ViewModel
 		private string _description;
 		private DateTime? _lastUpdated;
 		
-		public OfflineAddInsViewModelBase(ManagedAddIn addIn)
+		public OfflineAddInsViewModel(ManagedAddIn addIn)
 			: base()
 		{
 			Initialize(addIn);
 		}
 		
-		public OfflineAddInsViewModelBase(IAddInManagerServices services, ManagedAddIn addIn)
+		public OfflineAddInsViewModel(IAddInManagerServices services, ManagedAddIn addIn)
 			: base(services)
 		{
 			Initialize(addIn);
@@ -151,6 +151,24 @@ namespace ICSharpCode.AddInManager2.ViewModel
 			}
 		}
 		
+		public override bool IsExternallyReferenced
+		{
+			get
+			{
+				if (_addIn != null)
+				{
+					// The AddIn is externally referenced, if it's .addin file doesn't reside in
+					// somewhere in application path (preinstalled AddIns) or in config path (usually installed AddIns).
+					return !FileUtility.IsBaseDirectory(FileUtility.ApplicationRootPath, _addIn.FileName)
+						&& !FileUtility.IsBaseDirectory(SD.PropertyService.ConfigDirectory, _addIn.FileName);
+				}
+				else
+				{
+					return false;
+				}
+			}
+		}
+		
 		public override bool IsPreinstalled
 		{
 			get
@@ -452,6 +470,8 @@ namespace ICSharpCode.AddInManager2.ViewModel
 
 		public override void RemovePackage()
 		{
+			ClearReportedMessages();
+			
 			if (_addIn.Manifest.PrimaryIdentity == "ICSharpCode.AddInManager2")
 			{
 				MessageService.ShowMessage("${res:AddInManager2.CannotRemoveAddInManager}", "${res:AddInManager.Title}");
@@ -481,21 +501,29 @@ namespace ICSharpCode.AddInManager2.ViewModel
 		
 		public override void CancelInstallation()
 		{
+			ClearReportedMessages();
+			
 			AddInManager.Setup.CancelInstallation(_addIn);
 		}
 		
 		public override void CancelUpdate()
 		{
+			ClearReportedMessages();
+			
 			AddInManager.Setup.CancelUpdate(_addIn);
 		}
 		
 		public override void CancelUninstallation()
 		{
+			ClearReportedMessages();
+			
 			AddInManager.Setup.CancelUninstallation(_addIn);
 		}
 
 		public override void DisablePackage()
 		{
+			ClearReportedMessages();
+			
 			if (_addIn == null)
 			{
 				return;
@@ -547,6 +575,8 @@ namespace ICSharpCode.AddInManager2.ViewModel
 		
 		public override void ShowOptions()
 		{
+			ClearReportedMessages();
+			
 			AddInTreeNode dummyNode = new AddInTreeNode();
 			foreach (KeyValuePair<string, ExtensionPath> pair in _addIn.Paths)
 			{
@@ -559,5 +589,11 @@ namespace ICSharpCode.AddInManager2.ViewModel
 				_addIn.Name + " " + SD.ResourceService.GetString("AddInManager.Options"),
 				dummyNode);
 		}
+		
+		private void ClearReportedMessages()
+		{
+			// Notify about new operation
+			AddInManager.Events.OnOperationStarted();
+		}
 	}
 }